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Journal articles on the topic 'TiO2 as a photocatalyst'
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1
Tang, Jian Jun, and Shao Feng Li. "Organic Pollutants Decomposition by TiO2 Visible-Light Photocatalysis with H2O2 Assistance." Advanced Materials Research 807-809 (September 2013): 402–9. http://dx.doi.org/10.4028/www.scientific.net/amr.807-809.402.
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The effects of crystalline structure (Anatase and Rutile) and H2O2 addition on TiO2 visible-light photocatalysis were studied, which used reactive brilliant red X-3B and phenol as model pollutants. The results indicated that reactive brilliant red X-3B could be degradated by the two form TiO2(anatase or rutile) under visible-irradiation with the assistance of H2O2, however, when the surface sites of TiO2 photocatalysts were preeminently occupied by CO32-, photodecomposition could not be processed. Phenol could also be degradated by the two form TiO2 under visible-irradiation with the assistance of H2O2, rutile TiO2 exhibited a better photocatalytic activity, and its degradation ratio could be 80% after 120 min of reaction. The concentration of the ring intermediates detected during phenol decomposition was evidently higher when using rutile TiO2 as photocatalyst, and the presence of hydroxyl radical inhibitor (tert-butyl alcohol or methanol) had great effects on the degradation efficiency of rutile TiO2, but had less effects on anatase TiO2. The degradation of phenol occurred mainly in the solution when using rutile TiO2 as photocatalyst, and in contrast, the degradation occurred mainly at the TiO2 particles surface when using anatase TiO2 as photocatalyst.
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Shen, Yan Qin, and Hai Liang Wu. "The Photo-Catalytic Activity of Cu2+-Doped TiO2 and Applications in the Self-Cleaning Performance of Textile Wall Fabrics." Advanced Materials Research 557-559 (July 2012): 1475–78. http://dx.doi.org/10.4028/www.scientific.net/amr.557-559.1475.
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TiO2 photocatalyst and copper-doped titania (Cu/TiO2) photocatalyst were prepared and both photocatalysts were used in the self-cleaning finishing of wall fabrics. XRD showed that the nanometer materials and textile wall fabrics were a good combination. By comparing the self-cleaning effects of two kinds of photocatalysts, the results demonstrate that textile wall fabrics finished with Cu2+-doped TiO2 photocatalyst have better self-cleaning effect under visible light.
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You, Wei. "Research Progresses and Development Trends of High-Efficacy Photocatalysts." Applied Mechanics and Materials 496-500 (January 2014): 532–35. http://dx.doi.org/10.4028/www.scientific.net/amm.496-500.532.
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Progresses of research on high-efficacy photocatalyst were introduced in this paper. Firstly, efficiency-strengthening methods of TiO2-serie photocatalysts were summarized basing on collected literatures, including photosensitization, alloying, moreover, novel photocatalysis materials and technologies and probable development tendencies in the future were introduced, such as broad-spectrum photocatalysts, broad-energy and energy-sensitive catalysts and high-efficacy controllable high-power photocatalysis materials and equipments.
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Jiang, Zhuoying, Sameera Wickramasinghe, Yu Hsin Tsai, Anna Cristina S. Samia, David Gurarie, and Xiong Yu. "Modeling and Experimental Studies on Adsorption and Photocatalytic Performance of Nitrogen-Doped TiO2 Prepared via the Sol–Gel Method." Catalysts 10, no. 12 (December 11, 2020): 1449. http://dx.doi.org/10.3390/catal10121449.
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Nitrogen-doped TiO2 has a great potential as a photocatalyst under visible light irradiation with applications in the removal of air and water pollutants, and the treatment of bacterial contaminations. In this study, nitrogen-doped TiO2 nanoparticles were synthesized via the sol–gel method and a post-annealing heat treatment approach. The effects of annealing treatment on the photocatalyst crystalline size and degree of crystallinity were analyzed. Methylene blue dye was used as the model water contaminant for the evaluation of the photoactivity of the synthesized nitrogen-doped TiO2 nanoparticles. The degradation of methylene blue was attributed to three mechanisms, i.e., adsorption, photocatalysis, and direct light photolysis. A kinetic model was developed to distinguish the impact of these three different mechanisms on the removal of contaminants. Adsorption and photocatalysis are heterogeneous processes for removing water organic contaminants. The characterization analysis demonstrates that they are relevant to the microstructures and surface chemical compositions of nitrogen-doped TiO2 photocatalysts. The processing–structure–performance relationship helped to determine the optimal processing parameters for nitrogen-doped TiO2 photocatalyst to achieve the best performance. While we used methylene blue as the model contaminant, the generalized quantitative model framework developed in this study can be extended to other types of contaminants after proper calibration.
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Xia, Qibin, Zhong Li, Hongxia Xi, and Kefeng Xu. "Activation Energy for Dibenzofuran Desorption from Fe3+/TiO2 and Ce3+/TiO2 Photocatalysts Coated onto Glass Fibres." Adsorption Science & Technology 23, no. 5 (June 2005): 357–66. http://dx.doi.org/10.1260/026361705774355469.
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In this work, TiO2, Fe3+/TiO2 and Ce3+/TiO2 photocatalytic films were respectively immobilized on glass fibres via the sol—gel technique to prepare supported photocatalysts. Temperature programmed desorption (TPD) experiments were conducted to measure the TPD curves for the removal of dibenzofuran from these photocatalysts, from which the activation energy for dibenzofuran desorption from the photocatalyst surfaces was estimated. The results showed that the activation energies for dibenzofuran desorption from the photocatalysts TiO2, Ce3+/TiO2 and Fe3+/TiO2 coated separately onto the glass fibres were 16.41 kJ/mol, 22.55 kJ/mol and 33.59 kJ/mol, respectively, while the hardness values of the ions Fe3+, Ce3+ and Ti4+ were respectively 13.1 eV, 11.9 eV and 10.6 eV. The data indicated that the use of Fe3+ or Ce3+ ions for doping a TiO2 photo-catalyst increased the local hardness of the doped TiO2 photocatalyst surface. This, in turn, increased the activation energy for the desorption of dibenzofuran from such a TiO2 photocatalyst surface.
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Noguchi, H., A. Nakajima, T. Watanabe, and K. Hashimoto. "Removal of bromate ion from water using TiO2 and alumina-loaded TiO2 photocatalysts." Water Science and Technology 46, no. 11-12 (December 1, 2002): 27–31. http://dx.doi.org/10.2166/wst.2002.0712.
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The effects of pH and the surface charge of photocatalyst on photocatalytic reduction of bromate ions in water were examined by using TiO2 and alumina-loaded TiO2 photocatalysts. The amount of adsorbed bromate ion on TiO2 and the reduction rate of bromate ion by the TiO2 photocatalyst increased with lowering pH. It was suggested that the bromate ion adsorbed predominantly on the positively charged surface sites of TiO2 at lower pH, which thus promotes the rate of reduction. The iso-electric point of the TiO2 photocatalyst was shifted to the higher pH region by loading alumina on the TiO2 surface, which resulted in the increase of the adsorbed amount of bromate on the photocatalyst and the reduction rate of bromate ion by the photocatalyst at neutral pH. It was concluded from these results that the photocatalytic reduction of bromate ion can be promoted by pH control of water or by controlling the surface charge of the photocatalyst by loading alumina without pH control of water.
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Wahyuni, Endang Tri, Titi Rahmaniati, Aulia Rizky Hafidzah, Suherman Suherman, and Adhitasari Suratman. "Photocatalysis over N-Doped TiO2 Driven by Visible Light for Pb(II) Removal from Aqueous Media." Catalysts 11, no. 8 (August 5, 2021): 945. http://dx.doi.org/10.3390/catal11080945.
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The photocatalysis process over N-doped TiO2 under visible light is examined for Pb(II) removal. The doping TiO2 with N element was conducted by simple hydrothermal technique and using urea as the N source. The doped photocatalysts were characterized by DRUVS, XRD, FTIR and SEM-EDX instruments. Photocatalysis of Pb(II) through a batch experiment was performed for evaluation of the doped TiO2 activity under visible light, with applying various fractions of N-doped, photocatalyst mass, irradiation time, and solution pH. The research results attributed that N doping has been successfully performed, which shifted TiO2 absorption into visible region, allowing it to be active under visible irradiation. The photocatalytic removal of Pb(II) proceeded through photo-oxidation to form PbO2. Doping N into TiO2 noticeably enhanced the photo-catalytic oxidation of Pb(II) under visible light irradiation. The highest photocatalytic oxidation of 15 mg/L Pb(II) in 25 mL of the solution could be reached by employing TiO2 doped with 10%w of N content 15 mg, 30 min of time and at pH 8. The doped-photocatalyst that was three times repeatedly used demonstrated significant activity. The most effective process of Pb(II) photo-oxidation under beneficial condition, producing less toxic and handleable PbO2 and good repeatable photocatalyst, suggest a feasible method for Pb(II) remediation on an industrial scale.
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Li, Jiaxin, Zhi Chen, Jianfei Fang, Qian Yang, Xiuru Yang, Wan Zhao, Dantong Zhou, Xiaoxiao Qian, Chunxi Liu, and Jianzhong Shao. "Facile synthesis of TiO2 film on glass for the photocatalytic removal of rhodamine B and tetracycline hydrochloride." Materials Express 9, no. 5 (August 1, 2019): 437–43. http://dx.doi.org/10.1166/mex.2019.1522.
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Photocatalysis is one of the efficient approaches for pollution control in water. However, the traditional photocatalysts used for the removal of organic pollutants are in powder form, which makes it difficult to recover them from the suspended reaction system. On the contrary, thin film photocatalyst is easy to be retrieved and possesses unique feature for practical application. In present work, stable TiO2 sol suspension was prepared and amorphous TiO2 thin film was then immobilized upon glass substrate through facile spin coating method. The thickness of film could be simply controlled by changing the number of coatings, and anatase TiO2 film could be formed after calcination. The prepared thin films were characterized with X-ray diffraction (XRD), ultravioletvisible spectrophotometry (UV-vis), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The photodegradations of organic pollutants including colored dye and colorless antibiotic were tested and found to be thickness-dependent. Additionally, the prepared film photocatalst has good stability and may have potential applications in wastewater treatment.
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Budi, Iis Setyo, Indriana Kartini, and Eko Sri Kunarti. "Photoreduction of Pb(II) Using TiO2 Catalyst Modified with Fe3O4 Nanoparticles." Key Engineering Materials 840 (April 2020): 79–83. http://dx.doi.org/10.4028/www.scientific.net/kem.840.79.
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The TiO2/Fe3O4 nanoparticle has been successfully synthesized and the material is then applied as a photocatalyst to reduce Pb(II). The Fe3O4 was synthesized through sono-coprecipitation method using NH4OH as a precipitating agent. The coating TiO2 onto Fe3O4 was performed respectively via hydrolysis reaction and sol-gel process using ammonium sulfate and TTIP as a reagent of TiO2. This study investigated several parameters such as the effect of time, equilibrium state and material responsiveness toward ultraviolet light. The XRD measurement indicated the presence of Fe3O4 and TiO2 while TEM image displayed the photocatalyst had a nanosized particle with approximately 60 nm in size. An activity test at pH 4, the equilibrium of photoreduction process showed at 60 minutes. The kinetic parameter of Pb(II) reduction at various catalyst presented that TiO2/Fe3O4 nanoparticle had better reduction rate constant than that of TiO2. Reusing of TiO2/Fe3O4 photocatalysts showed the results of Pb (II) photoreduction were not significantly decrease and the results of photocatalysis were still better than TiO2.
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He, Kang, Yu Chen, and Mengjun Mei. "Study on influencing factors of photocatalytic performance of CdS/TiO2 nanocomposite concrete." Nanotechnology Reviews 9, no. 1 (November 27, 2020): 1160–69. http://dx.doi.org/10.1515/ntrev-2020-0074.
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AbstractIn this study, a high-energy ball mill was used to composite nano-TiO2 and CdS, and three kinds of nanocomposite photocatalysts TiO2, CdS/TiO2-R400, and CdS/TiO2-R600 were prepared, which can respond to visible light. The photocatalytic concrete test block was prepared by mixing the nanocomposite photocatalyst and other masses with cement by incorporation method. To study the effect of the photocatalyst content on the photocatalytic performance of nanoconcrete, a total of four catalyst contents (0, 2%, 5%, and 8%) were set. The effects of high-temperature treatment (400°C) and different light sources (ultraviolet and visible light) on photocatalytic efficiency were also considered. The results show that the catalytic efficiency of CdS/TiO2-R400 under two light sources is higher than that of the other two photocatalysts. Compared to ultraviolet light sources, the photocatalytic efficiency of CdS/TiO2 nanocomposite concrete under visible light is lower, and the efficiency is below 9%. The optimal amounts of CdS/TiO2 nanocomposite photocatalyst under ultraviolet and visible light are 2% and 5%, respectively. The high-temperature treatment can improve the photocatalytic performance of CdS/TiO2 nanocomposite photocatalyst by 2% to 3%.
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Hafizah, Nor, and Iis Sopyan. "Cement Bonded Sol-Gel TiO2 Powder Photocatalysis for Phenol Removal." Applied Mechanics and Materials 776 (July 2015): 271–76. http://dx.doi.org/10.4028/www.scientific.net/amm.776.271.
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Photocatalysis has been proven effective in controlling various environmental problems originated by pollutions both in liquid and gaseous phases. Titanium dioxide (TiO2) is well known the most practical photocatalyst as it has high photocatalytic efficiency, low band gap energy, and no toxicity. Various chemical methods have been tried to produce TiO2 photocatalyst powder with high activity. In this study, sol-gel method has been employed to produce nanosized TiO2 photocatalyst particles and its physical properties and photocatalytic activity in phenol degradation test were compared with the commercial TiO2 powder, Degussa P25. The synthesis process was carried out through hydrolysis of titanium tetraisopropoxide (TPT) and methanol where the molar ratio of water to TPT was monitored to control the hydrolysis rate. From X-Ray Diffraction (XRD) analysis, the sol-gel TiO2 powder obtained was fully in anatase structure with high crystallinity. Scanning Electron Microscope (SEM) measurement showed that the powder was in nanoto sub-micron size, spherical in shape, and tightly agglomerated. Thermal analysis confirmed that sol-gel derived amorphous TiO2 powder transformed to anatase phase after 400°C calcination. The test on photocatalytic performance conducted using aqueous solution of phenol as the representative of water pollutant examined in this study showed that the sol-gel TiO2 powder is more efficient in degrading phenol compared to one of the most active photocatalysts commercially available, Degussa P25.
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Le, Minh-Vien, Tai Huynh Huu, Oanh Nguyen Thi Kieu, Thang Ngo Manh, and Suong Ho Thi Ngoc. "Enhanced photocatalytic degradation performance of bisphenol A over TiO2-SiO2 photocatalyst by improving specific surface area under simulation natural light." Vietnam Journal of Catalysis and Adsorption 9, no. 4 (December 31, 2020): 49–57. http://dx.doi.org/10.51316/jca.2020.069.
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The application of natural light in photocatalytic process is a potential energy source. In this study, TiO2-SiO2 nanoparticles with outstandingly enhanced photocatalytic activity have been fabricated by sol-gel method. The prepared photocatalysts with different molar ratio of TiO2:SiO2 as 100:0; 95:5; 85:15 and 75:25 were denoted as TiO2, TS5, TS15 and TS25, respectively. Characterization of these photocatalysts was evaluated using transmission electron microscopy (TEM), X-ray diffraction (XRD), N2 Adsorption and Desorption isotherms method (Brunauer–Emmet–Teller, BET). The specific surface area was improved in TiO2-SiO2 photocatalyst namely 193.9 m2.g-1 (at molar ratio of TiO2:SiO2 of 95:5) compared to 33.6 m2.g-1 of TiO2. The crystallite size was calculated around 5 nm from XRD data and uniform particle size distribution was observed in TEM image. The photocatalytic experiments were performed with bisphenol A (BPA) as model compound of organic pollutant. The effect of various operation parameters such as initial concentration, initial solution pH and photocatalyst dosage has been investigated. The kinetic studies of the photocatalytic degradation BPA over TS5 followed the pseudo-first order (k=1.09×10-2 min-1) and degradation yield to be 82.4% BPA, at pH6.23, initial concentration to be 10 ppm and photocatalyst dosage to be 1.0 g.L-1. The photocatalyst TS5 maintained activity after four cycles and remained 78%. The TiO2-SiO2 composite photocatalyst has shown to be a promising heterogeneous photocatalyst for organic degradation.
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Ren, Yu, Yuze Dong, Yaqing Feng, and Jialiang Xu. "Compositing Two-Dimensional Materials with TiO2 for Photocatalysis." Catalysts 8, no. 12 (November 28, 2018): 590. http://dx.doi.org/10.3390/catal8120590.
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Energy shortage and environmental pollution problems boost in recent years. Photocatalytic technology is one of the most effective ways to produce clean energy—hydrogen and degrade pollutants under moderate conditions and thus attracts considerable attentions. TiO2 is considered one of the best photocatalysts because of its well-behaved photo-corrosion resistance and catalytic activity. However, the traditional TiO2 photocatalyst suffers from limitations of ineffective use of sunlight and rapid carrier recombination rate, which severely suppress its applications in photocatalysis. Surface modification and hybridization of TiO2 has been developed as an effective method to improve its photocatalysis activity. Due to superior physical and chemical properties such as high surface area, suitable bandgap, structural stability and high charge mobility, two-dimensional (2D) material is an ideal modifier composited with TiO2 to achieve enhanced photocatalysis process. In this review, we summarized the preparation methods of 2D material/TiO2 hybrid and drilled down into the role of 2D materials in photocatalysis activities.
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Bertram, John, and Matthew Nee. "A Buoyant, Microstructured Polymer Substrate for Photocatalytic Degradation Applications." Catalysts 8, no. 10 (October 22, 2018): 482. http://dx.doi.org/10.3390/catal8100482.
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Microbubble fabrication of poly(dimethylsiloxane) (PDMS) beads with incorporated TiO2 provides a low-density, microstructured photocatalyst that is buoyant in water. This approach surmounts many of the challenges traditionally encountered in the generation of buoyant photocatalysts, an area which is critical for the implementation of widespread environmental cleaning of organic pollutants in water resources. Because the incorporation into the polymer bead surface is done at low temperatures, the crystal structure of TiO2 is unaltered, ensuring high-quality photocatalytic activity, while PDMS is well-established as biocompatible, temperature stable, and simple to produce. The photocatalyst is shown to degrade methylene blue faster than other buoyant, TiO2-based photocatalysts, and only an order of magnitude less than direct suspension of an equivalent amount of photocatalyst in solution, even though the photocatalyst is only present at the surface of the solution. The reusability of the TiO2/PDMS beads is also strong, showing no depreciation in photocatalytic activity after five consecutive degradation trials.
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Zhang, Qing Wei, Wei Xie, Bao Hong Shen, Qiang Xie, and Xiao Liang Li. "Preparation of Magnetically Separable Composite Photocatalyst: Titania Coated Magnetic Activated Carbon." Applied Mechanics and Materials 719-720 (January 2015): 145–56. http://dx.doi.org/10.4028/www.scientific.net/amm.719-720.145.
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In the present work, the embedded-type TiO2/magnetic activated carbon (TiO2/MAC) photocatalysts were prepared. The MAC support was manufactured by one-step method and the TiO2coated on the surface of MAC was prepared by sol-gel method. Its crystalline structural properties, morphology, magnetic performances and pore texture were characterized by XRD, SEM, TEM, ultraviolet-visible absorption spectra (Uv-vis), vibrating sample magnetometry (VSM) and N2adsorption isotherm. Characterization results showed that TiO2was highly dispersed on the surface of MAC support in the form of anatase with a particle size of 10 nm. Obtained TiO2/MAC photocatalysts were applied to treatment of contaminant phenol in aqueous solution. The phenol removal percentage by TiO2/MAC photocatalyst is as high as 94% after three cycles. In addition, photocatalytic degradation of phenol in water was examined using TiO2/MAC photocatalysts. The results show that 4wt% Fe3O4was suitable to prepare the support of TiO2/MAC composite. The phenol removal percentage by TiO2/MAC photocatalyst is as high as 94% after three cycles. However, the adsorption capability of photocatalyst disappears after six cycles, while its phenol removal percentage via photodegradation is still as high as 60%. Meanwhile, the used TiO2/MAC photocatalyst after six cycles still maintains good magnetic stability because the majority of magnetic particles are embedded into the bulk of carbon matrix. And the embedded structure could still meet the requirement of magnetic separation by an external magnetic field.
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Yamashita, Hiromi, Yoshikatsu Nishida, Osamu Chiyoda, Hiroyuki Nose, Masaki Narisawa, Tesutaro Ohmichi, and Iwao Katayama. "Design of Efficient TiO2/SiC Photocatalysts from TiC-SiC Nano Particles for Degradation of Organic Pollutants Diluted in Water." Materials Science Forum 510-511 (March 2006): 9–12. http://dx.doi.org/10.4028/www.scientific.net/msf.510-511.9.
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TiO2/SiC was prepared by oxidizing the TiC-SiC precursor obtained by carbothermic reduction process of TiO2-SiO2 binary oxide. An XRD analysis indicated the formation of the mixture of anatase and rutile phases of TiO2 crystalline after the oxidation of TiC-SiC sample. TiO2/SiC photocatalyst exhibited a higher photocatalytic reactivity than TiO2-SiO2 binary oxide prepared by the conventional sol-gel method. These results indicate the advantages of SiC nano powders as catalyst support of the TiO2 photocatalysts, and TiO2/SiC photocatalyst is effective for the degradation of organic compounds diluted in water.
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Lee, Jun-Cheol, Anantha-Iyengar Gopalan, Gopalan Sai-Anand, Kwang-Pill Lee, and Wha-Jung Kim. "Preparation of Visible Light Photocatalytic Graphene Embedded Rutile Titanium(IV) Oxide Composite Nanowires and Enhanced NOx Removal." Catalysts 9, no. 2 (February 11, 2019): 170. http://dx.doi.org/10.3390/catal9020170.
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The quest for developing highly efficient TiO2-based photocatalysts is continuing and, in particular, evolving a new strategy is an important aspect in this regard. In general, much effort has been devoted to the anatase TiO2 modifications, despite there being only a few recent studies on rutile TiO2 (rTiO2). To the best of our knowledge, studies on the preparation and characterization of the photocatalysts based on the intentional inclusion of graphene (G) into rTiO2 nanostructures have not been reported yet. Herein, we develop a new type of TiO2-based photocatalyst comprising of G included pure rTiO2 nanowire (abbreviated as rTiO2(G) NW) with enhanced visible light absorption capability. To prepare rTiO2(G) NW, the G incorporated titanate electrospun fibers were obtained by electrospinning and subsequently heat treated at various temperatures (500 to 800 °C). Electrospinning conditions were optimized for producing good quality rTiO2(G) NW. The rTiO2(G) NW and their corresponding samples were characterized by appropriate techniques such as X-ray diffraction (XRD), scanning electron microscopy, high-resolution transmission electron microscopy and UV-vis diffuse reflectance spectroscopy to ascertain their material characteristics. XRD results show that the lattice strain occurs upon inclusion of G. We present here the first observation of an apparent bandgap lowering because of the G inclusion into TiO2 NW. While anatase TiO2 NW exhibited poor visible light photocatalysis towards NOx removal, the rTiO2(G) NW photocatalyst witnessed a significantly enhanced (~67%) photocatalytic performance as compared to anatase TiO2(G) NW. We concluded that the inclusion of G into rTiO2 nanostructures enhances the visible light photoactivity. A plausible mechanism for photocatalysis is suggested.
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Divya, Neetu, Ajay Bansal, and Asim K. Jana. "Photocatalytic Activity of Transition Metal Ion Doped Titania for Amaranth Dye Degradation." Materials Science Forum 712 (February 2012): 85–104. http://dx.doi.org/10.4028/www.scientific.net/msf.712.85.
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nanosized titania catalyst and transition metal doped titania photocatalysts such as TiO2/Ag, TiO2/Cu and TiO2/Ag/Cu were used for photocatalytic degradation of Amaranth. Doping of titania was done with impregnation method. Photocatalytic activity was checked in terms of percentages of decolorization, COD removal and TOC removal. It was found that TiO2/Ag/Cu doped photocatalyst was more effective for Amaranth dye degradation under feasible treatment conditions. For decolorization, Amaranth took irradiation time of 210 min with UV/H2O2 but it took only 60 min with TiO2/Ag/Cu doped photocatalyst. Only 29% COD and 49% TOC removal were achieved with homogeneous photodegradation, whereas with TiO2/Ag/Cu heterogeneous photodegradation, 100% COD and 98% TOC removal was achieved in 9h for 50 ppm aqueous Amaranth solution. The relative electrical energy consumption per order of magnitude for photocatalytic degradation of Amaranth was considerably lower with TiO2/Ag/Cu catalyst than that with UV/H2O2 and other combinations of doped photocatalyst. The photocatalysts were characterized using XRD and TEM analysis.
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Young, C., T. M. Lim, K. Chiang, and R. Amal. "Photocatalytic degradation of toluene by platinized titanium dioxide photocatalysts." Water Science and Technology 50, no. 4 (August 1, 2004): 251–56. http://dx.doi.org/10.2166/wst.2004.0276.
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A photoreactor has been set up to study the photodegradation of volatile organic compound (VOC) in situ. In the reactor, TiO2 and Pt/TiO2 photocatalysts were immobilized on to UV-transparent quartz support. Scanning electron microscope (SEM) studies and Brunauer-Emmett-Teller (BET) surface area measurements revealed that the quartz fiber support was mostly coated with catalyst with a total surface area of 4.0 ± 0.3 m2/g. The photocatalytic activity of the photocatalysts was evaluated for the photodegradation of 160 ppm toluene-laden air. It was found that 50-70% of toluene was degraded within the first 5 min of UV illumination. Both TiO2 and Pt/TiO2 photocatalysts suffered from deactivation after 18 hours of continuous operation, and the photocatalysts' activity was significantly reduced. However, platinization doubled the photocatalyst life and delayed the onset of de-activation. The presence of moisture was found to shift the onset of catalyst de-activation to an earlier time. It is concluded that the de-activation of the photocatalyst was due to the accumulation of intermediates on the photocatalysts surface preventing the toluene being adsorbed on the photocatalyst surface for degradation.
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Zhou, Tong-Tong, Feng-He Zhao, Yu-Qian Cui, Li-Xiang Chen, Jia-Shu Yan, Xiao-Xiong Wang, and Yun-Ze Long. "Flexible TiO2/PVDF/g-C3N4 Nanocomposite with Excellent Light Photocatalytic Performance." Polymers 12, no. 1 (December 31, 2019): 55. http://dx.doi.org/10.3390/polym12010055.
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As the world faces water shortage and pollution crises, the development of novel visible light photocatalysts to purify water resources is urgently needed. Over the past decades, most of the reported photocatalysts have been in powder or granular forms, creating separation and recycling difficulties. To overcome these challenges, a flexible and recyclable heterostructured TiO2/polyvinylidene fluoride/graphitic carbon nitride (TiO2/PVDF/g-C3N4) composite was developed by combining electrospinning, sintering and hydrothermal methods. In the composite, PVDF was used as a support template for removing and separating the photocatalyst from solution. Compared with pure TiO2, the TiO2/PVDF/g-C3N4 composite exhibited the extended light capture range of TiO2 into the visible light region. The photogenerated carriers were efficiently transferred and separated at the contact interface between TiO2 and g-C3N4 under visible light irradiation, which consequently increased the photocatalytic activity of the photocatalyst. In addition, the flexible composites exhibited excellent self-cleaning properties, and the dye on the photocatalysts was completely degraded by the as-prepared materials. Based on the intrinsic low cost, recyclability, absorption of visible light, facile synthesis, self-cleaning properties and good photocatalytic performances of the composite, the photocatalyst is expected to be used for water treatment.
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Lettieri, Stefano, Michele Pavone, Ambra Fioravanti, Luigi Santamaria Amato, and Pasqualino Maddalena. "Charge Carrier Processes and Optical Properties in TiO2 and TiO2-Based Heterojunction Photocatalysts: A Review." Materials 14, no. 7 (March 27, 2021): 1645. http://dx.doi.org/10.3390/ma14071645.
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Photocatalysis based technologies have a key role in addressing important challenges of the ecological transition, such as environment remediation and conversion of renewable energies. Photocatalysts can in fact be used in hydrogen (H2) production (e.g., via water splitting or photo-reforming of organic substrates), CO2 reduction, pollution mitigation and water or air remediation via oxidation (photodegradation) of pollutants. Titanium dioxide (TiO2) is a “benchmark” photocatalyst, thanks to many favorable characteristics. We here review the basic knowledge on the charge carrier processes that define the optical and photophysical properties of intrinsic TiO2. We describe the main characteristics and advantages of TiO2 as photocatalyst, followed by a summary of historical facts about its application. Next, the dynamics of photogenerated electrons and holes is reviewed, including energy levels and trapping states, charge separation and charge recombination. A section on optical absorption and optical properties follows, including a discussion on TiO2 photoluminescence and on the effect of molecular oxygen (O2) on radiative recombination. We next summarize the elementary photocatalytic processes in aqueous solution, including the photogeneration of reactive oxygen species (ROS) and the hydrogen evolution reaction. We pinpoint the TiO2 limitations and possible ways to overcome them by discussing some of the “hottest” research trends toward solar hydrogen production, which are classified in two categories: (1) approaches based on the use of engineered TiO2 without any cocatalysts. Discussed topics are highly-reduced “black TiO2”, grey and colored TiO2, surface-engineered anatase nanocrystals; (2) strategies based on heterojunction photocatalysts, where TiO2 is electronically coupled with a different material acting as cocatalyst or as sensitizer. Examples discussed include TiO2 composites or heterostructures with metals (e.g., Pt-TiO2, Au-TiO2), with other metal oxides (e.g., Cu2O, NiO, etc.), direct Z-scheme heterojunctions with g-C3N4 (graphitic carbon nitride) and dye-sensitized TiO2.
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Nyamukamba, P., L. Tichagwa, S. Mamphweli, and L. Petrik. "Silver/Carbon Codoped Titanium Dioxide Photocatalyst for Improved Dye Degradation under Visible Light." International Journal of Photoenergy 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/3079276.
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Herein, we report the synthesis of quartz supported TiO2 photocatalysts codoped with carbon and silver through the hydrolysis of titanium tetrachloride followed by calcination at 500°C. The prepared samples were characterized by UV-Vis diffuse reflectance spectroscopy, high resolution scanning electron microscopy (HRSEM), Raman spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Codoping of TiO2 with Ag and carbon resulted in an increase in the surface area of the photocatalyst and altered the ratio of the anatase to rutile phase. The absorption edge of all the doped TiO2 photocatalysts redshifted and the band gap was reduced. The lowest band gap of 1.95 eV was achieved by doping with 0.5% Ag. Doping TiO2 using carbon as the only dopant resulted in a quartz supported photocatalyst that showed greater photocatalytic activity towards methyl orange than undoped TiO2 and also all codoped TiO2 photocatalysts under visible light irradiation.
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Fu, Zhongtian, Song Zhang, and Zhongxue Fu. "Preparation of Multicycle GO/TiO2 Composite Photocatalyst and Study on Degradation of Methylene Blue Synthetic Wastewater." Applied Sciences 9, no. 16 (August 10, 2019): 3282. http://dx.doi.org/10.3390/app9163282.
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A series of composite photocatalysts were prepared by using graphene oxide (GO) prepared by modified Hummers method and TiO2 hydrogel prepared by using butyl titanate as raw materials. The composite photocatalyst was characterized through scanning electron microscope（SEM）, x ray diffraction （XRD）, and Raman spectroscopy, and the degradation effect of pure TiO2 and composite photocatalyst on methylene blue (MB) dye wastewater under different experimental conditions was studied. The results showed that TiO2 in composite photocatalyst was mainly anatase phase and its photocatalytic activity was better than pure TiO2. When the addition of GO reached 15 wt%, the photocatalytic activity was the highest. When 200 mg composite photocatalyst was added to 200 mL synthetic wastewater with a concentration of 10 mg/L and an initial pH of about 8, the degradation rate could reach 95.8% after 2.5 h. It is presumed that the photogenerated charges of GO/TiO2 composite photocatalyst may directly destroy the luminescent groups in the MB molecule and thus decolorize the wastewater, and no other new luminescent groups are generated during the treatment.
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Guan, Hua Nan. "Enhancement of Photocatalytic Oxidation Degradation of Methyl Orange by WO3/TiO2 Photocatalysts under UV Irradiation." Applied Mechanics and Materials 341-342 (July 2013): 191–94. http://dx.doi.org/10.4028/www.scientific.net/amm.341-342.191.
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Nanosized WO3-doped TiO2 photocatalysts were synthesized by a simple hydrothermal method, and characterized by scanning electron microscopy (SEM) and BET surface area analyzer. The photocatalytic activity of undoped TiO2 and WO3 doped TiO2 photocatalysts was evaluated by the photocatalytic oxidation degradation of methyl orange in aqueous solution. The results show that the photocatalytic activity of the WO3 doped TiO2 photocatalyst is much higher than that of undoped TiO2.
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Yuan, Chung Shin, Hsieh Hung Tsai, Jeng Fong Wu, Bo Cheng Guo, and Chung Hsuang Hung. "Photocatalytic Degradation of Gaseous Acetone by a Self-Prepared Nano-Sized Composite TiO2/In2O3/SnO2 Film Photocatalyst." Advanced Materials Research 287-290 (July 2011): 1581–84. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.1581.
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The objective of this study is to decompose gaseous acetone ((CH3)2CO) by a self-prepared nano-sized composite TiO2/In2O3/SnO2 film photocatalyst that was prepared by a multi-target vacuum sputter operating at a vacuum pressure of 3 mtorr. The operating parameters investigated for the sputtering process included oxygen to argon ratio (O2/Ar), sputtering temperature, substrate materials, substrate layers, and sputtering duration. The nano-sized composite TiO2/In2O3/SnO2 film photocatalyst was mainly composed of anatase with a few rutile. The surface roughness of the TiO2/In2O3/SnO2 film photocatalyst in terms of RMS ranged from 2.292 to 7.533 nm, while the thickness of the single- and double-layer film photocatalysts were 473.5 and 506.0 nm, respectively. Gaseous acetone was initially injected into and further degraded in a self-designed batch photocatalytic reactor containing the nano-sized composite TiO2/In2O3/SnO2 film photocatalyst. Experimental results indicated that the highest acetone degradation efficiency of 99.9% was obtained at 50°C and 1 atm with the incident of near-UV illuminated by a fluorescent black light lamp. Under the incidence of blue light (430-500 nm), the reaction rates of acetone decomposition were 2.353x10-5 and 3.478x10-5 μmole/cm2-sec for using single- and double-layer TiO2/In2O3/SnO2 film photocatalysts, respectively.
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Bak, Tadeusz, Truls Norby, Janusz Nowotny, Maria K. Nowotny, and Nikolaus Sucher. "Titanium Dioxide Photocatalyst - Unresolved Problems." Solid State Phenomena 162 (June 2010): 77–90. http://dx.doi.org/10.4028/www.scientific.net/ssp.162.77.
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The present work considers the performance of TiO2-based photosensitive oxide semiconductors as photocatalysts for water purification. This paper brings together the concepts of solid state chemistry for nonstoichiometric compounds and the concepts of photocatalysis in order to discuss the reactivity between TiO2 and water including microorganisms (bacteria and viruses). The performance of TiO2 photocatalysts are considered in terms of a model of photoelectrochemical cell. The experimental data on photocatalytic removal of microorganisms from water are considered in terms of the effect of several properties, including pH, dispersion, light intensity, and temperature. It is argued that correct understanding of the performance of TiO2 photocatalysts requires recognition that properties of TiO2, which is a nonstoichiometric compound, are determined by defect disorder and the related ability to donate or accept electrons. The photocatalytic properties of TiO2 are considered in terms of the reactivity of both anodic and cathodic sites with water and the related charge transfer at the TiO2/H2O interface. It is shown that the formation of well defined photocatalysts requires knowledge of mass and charge transfer during processing and performance, respectively. The main hurdles in the development of high-performance photocatalysts are discussed.
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Zhao, Wan, Xiuru Yang, Chunxi Liu, Xiaoxiao Qian, Yanru Wen, Qian Yang, Tao Sun, Wenya Chang, Xin Liu, and Zhi Chen. "Facile Construction of All-Solid-State Z-Scheme g-C3N4/TiO2 Thin Film for the Efficient Visible-Light Degradation of Organic Pollutant." Nanomaterials 10, no. 4 (March 25, 2020): 600. http://dx.doi.org/10.3390/nano10040600.
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The increasing discharge of dyes and antibiotic pollutants in water has brought serious environmental problems. However, it is difficult to remove such pollutants effectively by traditional sewage treatment technologies. Semiconductor photocatalysis is a new environment-friendly technique and is widely used in aqueous pollution control. TiO2 is one of the most investigated photocatalysts; however, it still faces the main drawbacks of a poor visible-light response and a low charge-separation efficiency. Moreover, powder photocatalyst is difficult to be recovered, which is another obstacle limiting the practical application. In this article, g-C3N4/TiO2 heterojunction is simply immobilized on a glass substrate to form an all-solid-state Z-scheme heterojunction. The obtained thin-film photocatalyst was characterized and applied in the visible-light photodegradation of colored rhodamine B and tetracycline hydrochloride. The photocatalytic performance is related to the deposited layers, and the sample with five layers shows the best photocatalytic efficiency. The thin-film photocatalyst is easy to be recovered with stability. The active component responsible for the photodegradation is identified and a Z-scheme mechanism is proposed.
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Song, Yong Woo, Min Young Kim, Min Hee Chung, Young Kwon Yang, and Jin Chul Park. "NOx-Reduction Performance Test for TiO2 Paint." Molecules 25, no. 18 (September 7, 2020): 4087. http://dx.doi.org/10.3390/molecules25184087.
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In South Korea, the gradual increase in particulate matter generation has received significant attention from central and local governments. Exhaust gas, which contains nitrogen oxides (NOx), is one of the main sources of particulate matter. In this study, the reduction of NOx using a coating material mixed with a titanium dioxide (TiO2) photocatalyst was demonstrated. The NOx reduction performance of the TiO2 photocatalyst-infused coating was evaluated by applying the ISO 22197-1: 2007 standard. Subsequently, the performance was evaluated by changing the NO gas concentration and ultraviolet (UV)-A irradiance under standard experimental conditions. It was determined that NOx reduction can be achieved even if the NO gas concentration and UV-A irradiance are lower than those under the standard conditions when the TiO2 photocatalyst-infused coating was used. This study revealed that NOx reduction can be realized through TiO2 photocatalyst-infused coating in winter or cloudy days with a low solar altitude. It was also confirmed that compared with the UV-A irradiance, the NO gas concentration has a greater effect on the NOx reduction performance of the TiO2 photocatalyst-infused coating. These findings can be used to evaluate a variety of construction materials with TiO2 photocatalysts in the future.
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Hong, Zhang Lian, Fu Rong Zhao, Pei Song Tang, and Min Quan Wang. "Effect of Low Frequency and Power Ultrasonic Treatment on the Surface Adsorbed Organics and Visible Light Photocatalysis Activity of Nanosized TiO2 Photocatalyst." Key Engineering Materials 336-338 (April 2007): 2012–14. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.2012.
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The effect of ultrasonic treatment under low frequency and power condition on the surface adsorption state and photocatalysis activity of nanosized TiO2 photocatalyst was studied. Results obtained from UV-Vis absorption spectra revealed that obvious differences of adsorption state on TiO2 powder surface were found after ultrasonic treatment, which agreed with the DTA-TG results that the thermal peaks varied with increasing ultrasonic treatment time. Furthermore, the photocatalysis activity for methyl-orange solution under visible light irradiation (≥450 nm) varied in a similar way with increasing ultrasonic treatment time. Present study revealed that the ultrasonic treatment was an effective way to study the relation between the surface adsorption state and photocatalysis activity of present nanosize TiO2 photocatalyst.
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Kuo, Chao-Yin, Siang-En Syu, and Shiang-Ren Lin. "Photodegradation of aqueous bisphenol A using boric acid-doped titanium dioxide." Water Supply 16, no. 5 (April 25, 2016): 1410–16. http://dx.doi.org/10.2166/ws.2016.069.
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A high-photoactivity boric acid-doped titanium dioxide (B-doped TiO2) photocatalyst of the degradation of aqueous bisphenol A (BPA) under sunlight was synthesized and characterized by scanning electron microscope, X-ray photoelectron spectroscopy and UV-vis diffuse reflectance. The band gap energies of TiO2 and B-doped TiO2 (B/Ti mole ratio = 0.2%) were 3.01 and 2.98, showing that B-doped TiO2 could narrow the band gap of pure TiO2. In the photocatalytic kinetics of the photodegradation, the BPA photodegradation rate constants were 1.67 and 1.08 h−1, respectively. The BPA removal rate satisfies pseudo-first-order kinetics. Results showed that photocatalysts doped with boron displayed greater photodegradation (88% BPA removal) than pure TiO2 (65% BPA removal). Experimental results indicated that B-doped TiO2 not only was an effective photocatalyst, but also had considerable mineralization effects. The recycling test revealed that the photocatalyst remained effective after 10 uses, revealing the stability and reusability.
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Wawrzyniak, Beata, Antoni Waldemar Morawski, and Beata Tryba. "Preparation of TiO2-nitrogen-doped photocatalyst active under visible light." International Journal of Photoenergy 2006 (2006): 1–8. http://dx.doi.org/10.1155/ijp/2006/68248.
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This study examined the photocatalytic degradation of phenol and azo dyes such as Reactive Red 198 and Direct Green 99 by photocatalysis over amorphous hydrated titanium dioxide (TiO2· H2O) obtained directly from the sulphate technology installation modified in gaseous ammonia atmosphere. The photocatalysts were used in the solution and coated on the glass plate after sandblasting. The highest rate of phenol degradation in the solution was obtained for catalysts calcinated at 700°C (6.5% wt.), and the highest rate of dye decolorization was found for catalysts calcinated at 500°C and 600°C (ca. 40%–45%). Some TOC measurements of dye solutions were performed to check the rate of mineralization. On the glass plate, the decomposition of DG99 on TiO2/N 500 contrary to TiO2-P25 proceeded completely after 120 hours of visible light irradiation. The prolongation of the time of irradiation did not enhance DG99 degradation on TiO2-P25. The decomposition of the Direct Green 99 on TiO2/N 500 coated on the glass plate covered with liquid glass took place up to 24 hours of irradiation. The liquid layer on the glass plate which was covered with the photocatalyst reduced its activity. The nitrogen doping during calcinations under ammonia atmosphere is a new way of obtaining a photocatalyst which could have a practical application in water treatment system under broadened solar light spectrum as well as self-cleaning coatings.
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Gilja, Vanja, Zvonimir Katančić, Ljerka Kratofil Krehula, Vilko Mandić, and Zlata Hrnjak-Murgić. "Efficiency of TiO2 catalyst supported by modified waste fly ash during photodegradation of RR45 dye." Science and Engineering of Composite Materials 26, no. 1 (January 28, 2019): 292–300. http://dx.doi.org/10.1515/secm-2019-0017.
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AbstractThe waste fly ash (FA) material was subjected to chemical treatment with HCl at elevated temperature for a different time to modify its porosity. Modified FA particles with highest surface area and pore volume were further used as a support for TiO2 catalyst during FA/TiO2 nanocomposite preparation. The nanocomposite photocatalysts were obtained by in situ sol–gel synthesis of titanium dioxide in the presence of FA particles. To perform accurate characterization of modified FA and FA/TiO2 nanocomposite photocatalysts, gas adsorption-desorption analysis, X-ray diffraction, scanning electron microscopy, UV/Vis and Infrared spectroscopy were used. Efficiency evaluation of the synthesized FA/TiO2 nanocomposites was performed by following the removal of Reactive Red 45 (RR45) azo dye during photocatalytic treatment under the UV-A irradiation. Photocatalysis has been carried out up to five cycles with the same catalysts to investigate their stability and the possible reuse. The FA/TiO2 photocatalyst showed very good photocatalytic activity and stability even after the fifth cycles. The obtained results show that successfully modified waste fly ash can be used as very good TiO2 support.
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Yu, Fei, Xueting Bai, Changfu Yang, Lijie Xu, and Jie Ma. "Reduced Graphene Oxide–P25 Nanocomposites as Efficient Photocatalysts for Degradation of Bisphenol A in Water." Catalysts 9, no. 7 (July 17, 2019): 607. http://dx.doi.org/10.3390/catal9070607.
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Reduced graphene oxide–titanium dioxide photocatalyst (rGO–TiO2) was successfully synthesized by the hydrothermal method. The rGO–TiO2 was used as photocatalyst for the degradation of bisphenol A (BPA), which is a typical endocrine disruptor of the environment. Characterization of photocatalysts and photocatalytic experiments under different conditions were performed for studying the structure and properties of photocatalysts. The characterization results showed that part of the anatase type TiO2 was converted into rutile type TiO2 after hydrothermal treatment and 1% rGO–P25 had the largest specific surface area (52.174 m2/g). Photocatalytic experiments indicated that 1% rGO–P25 had the best catalytic effect, and the most suitable concentration was 0.5 g/L. When the solution pH was 5.98, the catalyst was the most active. Under visible light, the three photocatalytic mechanisms were ranked as follows: O2•− > •OH > h+. 1% rGO–P25 also had strong photocatalytic activity in the photocatalytic degradation of BPA under sunlight irradiation. 1% rGO–P25 with 0.5 g/L may be a very promising photocatalyst with a variety of light sources, especially under sunlight for practical applications.
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Yan, Jing, Xiaojuan Li, Bo Jin, Min Zeng, and Rufang Peng. "Synthesis of TiO2/Pd and TiO2/PdO Hollow Spheres and Their Visible Light Photocatalytic Activity." International Journal of Photoenergy 2020 (April 15, 2020): 1–9. http://dx.doi.org/10.1155/2020/4539472.
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A series of TiO2, TiO2/Pd, and TiO2/PdO hollow sphere photocatalysts was successfully prepared via a combination of hydrothermal, sol-immobilization, and calcination methods. The structure and optical properties of the as-prepared samples were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, Brunauer-Emmett-Telleranalysis, Barrett-Joyner-Halenda measurement, and UV-Vis diffuse reflectance spectroscopy. The photocatalysis efficiencies of all samples were evaluated through the photocatalytic degradation of rhodamine B under visible light irradiation. Results indicated that TiO2/PdO demonstrated a higher photocatalytic activity (the photocatalytic degradation efficiency could reach up to 100% within 40 min) than the other samples and could maintain a stable photocatalytic degradation efficiency for at least four cycles. Finally, after using different scavengers, superoxide and hydroxyl radicals were identified as the primary active species for the effectiveness of the TiO2/PdO photocatalyst.
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Edelmannová, Miroslava, Martin Reli, Lenka Matějová, Ivana Troppová, Lada Dubnová, Libor Čapek, Dana Dvoranová, Piotr Kuśtrowski, and Kamila Kočí. "Successful Immobilization of Lanthanides Doped TiO2 on Inert Foam for Repeatable Hydrogen Generation from Aqueous Ammonia." Materials 13, no. 5 (March 10, 2020): 1254. http://dx.doi.org/10.3390/ma13051254.
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We describe the successful possibility of the immobilization of a photocatalyst on foam, which is beneficial from a practical point of view. An immobilized photocatalyst is possible for use in a continuous experiment and can be easily separated from the reactor after the reaction concludes. Parent TiO2, La/TiO2, and Nd/TiO2 photocatalysts (containing 0.1 wt.% of lanthanide) were prepared by the sol-gel method and immobilized on Al2O3/SiO2 foam (VUKOPOR A) by the dip-coating method. The photocatalysts were investigated for the photocatalytic hydrogen generation from an aqueous ammonia solution under UVA light (365 nm). The evolution of hydrogen was compared with photolysis, which was limited to zero. The higher hydrogen generation was observed in the presence of 0.1 wt.% La/TiO2 than in 0.1 wt.% Nd/TiO2. This is, besides other things, related to the higher level of the conduction band, which was observed for 0.1 wt.% La/TiO2. The higher conduction band’s position is more effective for hydrogen production from ammonia decomposition.
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Sikirman, Arman, Jagannathan Krishnan, and Elvana Nerissa Mohamad. "Effect of Dopant Concentration of N, Fe Co-Doped TiO2 on Photodegradation of Methylene Blue under Ordinary Visible Light." Applied Mechanics and Materials 661 (October 2014): 34–38. http://dx.doi.org/10.4028/www.scientific.net/amm.661.34.
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The effect of dopant concentration on N, Fe co-doped TiO2 for photodegradation of methylene blue under ordinary visible light was investigated. The photocatalyst samples were prepared using solgel method with titanium tetraisopropoxide as precursor of titania. The dopant concentrations were varied from 0.50% and 1.0% and the calcinations temperature was fixed at 600oC. The prepared photocatalysts were characterized using XRD and FTIR to determine their physical properties. The results from XRD proved that photocatalyst with dopant concentration of 1.0% N, 1.0% Fe-TiO2 showing highly desirable properties in phase and crystal size. The results from FTIR revealed the presence of both the dopants in the samples. The effectivity of photocatalysts was tested by performing a standard batch photocatalytic degradation experiment with methylene blue as a model pollutant under ordinary visible light. The result showed that photocatalyst with high dopant concentration for both nitrogen and ferrum dopant (1.0 % N, 1.0% Fe-TiO2) yielded a maximum of 80.50% methylene blue degraded within five hours of irradiation time.
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Tapia-Tlatelpa, Tecilli, Jose Trull, and Luis Romeral. "In situ Decolorization Monitoring of Textile Dyes for an Optimized UV-LED/TiO2 Reactor." Catalysts 9, no. 8 (August 6, 2019): 669. http://dx.doi.org/10.3390/catal9080669.
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Heterogeneous photocatalysis, using photocatalysts in suspension to eliminate diverse contaminants, including textile wastewater, has several advantages. Nevertheless, current absorbance and decolorization measurements imply sample acquisition by extraction at a fixed rate with consequent photocatalyst removal. This study presents online monitoring for the decolorization of six azo dyes, Orange PX-2R (OP2), Remazol Black B133 (RB), Procion Crimson H-EXL (PC), Procion Navy H-EXL (PN), Procion Blue H-EXL (PB), and Procion Yellow H-EXL (PY), analyzing the spectrum measured in situ by using the light scattering provided by the photocatalyst in suspension. The results obtained have corroborated the feasibility of obtaining absorbance and decolorization measurements, avoiding disturbances in the process due to a decrease in the volume in the reactor.
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Ramli, Raihan Mahirah, Chong Fai Kait, and Abdul Aziz Omar. "Photocatalytic Degradation of Diisopropanolamine in Heterogeneous Photo-Fenton System." Advanced Materials Research 917 (June 2014): 160–67. http://dx.doi.org/10.4028/www.scientific.net/amr.917.160.
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Photodegradation of 100 ppm diisopropanolamine (DIPA) was studied employing heterogeneous photo-Fenton system using iron modified TiO2 photocatalyst. A series of Fe/TiO2 photocatalysts were prepared via hydrolysis-hydrothermal and wet impregnation methods. Photocatalysts prepared using wet impregnation method was found to have similar activity under both UV and visible light. Addition of H2O2 during the photodegradation study obviously promoted the COD removal efficiency. When stoichiometric concentration of H2O2 was added, as high as 80% of COD was removed within 1.5 h reaction. Further modification is required to increase the photocatalyst performance in photodegradation of DIPA.
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Tryba, Beata, Piotr Rychtowski, Agata Markowska-Szczupak, and Jacek Przepiórski. "Photocatalytic Decomposition of Acetaldehyde on Different TiO2-Based Materials: A Review." Catalysts 10, no. 12 (December 15, 2020): 1464. http://dx.doi.org/10.3390/catal10121464.
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Purification of air from the organic contaminants by the photocatalytic process has been confirmed to be very perspective. Although many various photocatalysts have been prepared and studied so far, TiO2 is still the most commonly used, because of its advantageous properties such as non-toxicity, relatively low cost and high stability. Surface modifications of TiO2 were extensively proceeded in order to increase photocatalytic activity of the photocatalyst under both UV and visible light activations. The intention of this review paper was to summarize the scientific achievements devoted to developing of TiO2-based materials considered as photocatalysts for the photocatalytic degradation of acetaldehyde in air. Influence of the preparation and modification methods on the parameters of the resultant photocatalyst is reviewed and discussed in this work. Affinity of the photocatalyst surfaces towards adsorption of acetaldehyde will be described by taking into account its physicochemical parameters. Impact of the contact time of a pollutant with the photocatalyst surface is analyzed and discussed with respect to both the degradation rate and mineralization degree of the contaminant. Influence of the photocatalyst properties on the mechanism and yield of the photocatalytic reactions is discussed. New data related to the acetaldehyde decomposition on commercial TiO2 were added, which indicated the different mechanisms occurring on the anatase and rutile structures. Finally, possible applications of the materials revealing photocatalytic activity are presented with a special attention paid to the photocatalytic purification of air from Volatile Organic Compounds (VOCs).
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Abed, Jehad, Nitul S. Rajput, Amine El Moutaouakil, and Mustapha Jouiad. "Recent Advances in the Design of Plasmonic Au/TiO2 Nanostructures for Enhanced Photocatalytic Water Splitting." Nanomaterials 10, no. 11 (November 15, 2020): 2260. http://dx.doi.org/10.3390/nano10112260.
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Plasmonic nanostructures have played a key role in extending the activity of photocatalysts to the visible light spectrum, preventing the electron–hole combination and providing with hot electrons to the photocatalysts, a crucial step towards efficient broadband photocatalysis. One plasmonic photocatalyst, Au/TiO2, is of a particular interest because it combines chemical stability, suitable electronic structure, and photoactivity for a wide range of catalytic reactions such as water splitting. In this review, we describe key mechanisms involving plasmonics to enhance photocatalytic properties leading to efficient water splitting such as production and transport of hot electrons through advanced analytical techniques used to probe the photoactivity of plasmonics in engineered Au/TiO2 devices. This work also discusses the emerging strategies to better design plasmonic photocatalysts and understand the underlying mechanisms behind the enhanced photoactivity of plasmon-assisted catalysts.
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Li, Long Feng, and Mao Lin Zhang. "Preparation of Cu2O-TiO2 Nanocomposite in Ethylene Glycol System and its Photocatalytic Activity under Visible Light Irradiation." Advanced Materials Research 236-238 (May 2011): 2102–5. http://dx.doi.org/10.4028/www.scientific.net/amr.236-238.2102.
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The nano-scale Cu2O-TiO2 couple oxide photocatalyst was successfully synthesized by the homogeneous hydrolysation, followed by the solvothermal crystallization and ethylene glycol-thermal reduction process, respectively. The obtained photocatalysts were characterized by X-ray diffraction (XRD), showing that the crystal phase composition and the crystal size of the prepared photocatalyst were affected by the ethylene glycol-thermal reduction temperature. The photocatalytic activity of Cu2O-TiO2 was also evaluated by the degradation of methyl orange (MO) as a model compound. The results showed that the prepared Cu2O-TiO2 exhibited higher photocatalytic activity for the decomposition of MO than the pure Cu2O and the commercial Degussa P25 TiO2 under visible light irradiation.
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Liu, Fu Sheng, Sheng Wang, Lian Lian Liu, and Huan Du. "Preparation and Photocatalysis Property of P-N Coupled Photocatalyst CoO/CdS/TiO2." Advanced Materials Research 512-515 (May 2012): 1677–82. http://dx.doi.org/10.4028/www.scientific.net/amr.512-515.1677.
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In this paper, p-n coupled photocatalyst CoO/CdS/TiO2 was prepared by method of impregnation. The structure and optical properties of CdS/TiO2 and CoO/CdS/TiO2 were characterized by XRD, SEM, BET and UV–vis DRS. The photocatalytic activities of the photocatalysts were evaluated by photocatalytic degradation of methyl orange, and the effect of photocorrosion of CdS in CoO/CdS/TiO2 was investigated by analyzing the cadmium concentration in the supernate collected after photocatalytic reactions. The results showed that p-n coupled photocatalyst CoO/CdS/TiO2 not only showed higher efficiency in degradation of methyl orange than CdS/TiO2, but also exhibited resistance against cadmium leakage under light irradiation. The mechanism of the photocorrosion-delaying by p–n junction was also discussed.
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Tu, Yu, Weihua Ao, Chunhong Wang, Tianyu Ren, Lijuan Zhang, Jiaxin Zhong, Wei Li, and Hao Ding. "Hydrolytic Modification of SiO2 Microspheres with Na2SiO3 and the Performance of Supported Nano-TiO2 Composite Photocatalyst." Materials 14, no. 10 (May 14, 2021): 2553. http://dx.doi.org/10.3390/ma14102553.
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Modified microspheres (SiO2-M) were obtained by the hydrolytic modification of silicon dioxide (SiO2) microspheres with Na2SiO3, and then, SiO2-M was used as a carrier to prepare a composite photocatalyst (SiO2-M/TiO2) using the sol-gel method; i.e., nano-TiO2 was loaded on the surface of SiO2-M. The structure, morphology, and photocatalytic properties of SiO2-M/TiO2 were investigated. Besides, the mechanism of the effect of SiO2-M was also explored. The results show that the hydrolytic modification of Na2SiO3 coated the surface of SiO2 microspheres with an amorphous SiO2 shell layer and increased the quantity of hydroxyl groups. The photocatalytic performance of the composite photocatalyst was slightly better than that of pure nano-TiO2 and significantly better than that of the composite photocatalyst supported by unmodified SiO2. Thus, increasing the loading capacity of nano-TiO2, improving the dispersion of TiO2, and increasing the active surface sites are essential factors for improving the functional efficiency of nano-TiO2. This work provides a new concept for the design of composite photocatalysts by optimizing the performance of the carrier.
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Riaz, Nadia, Bustam-Khalil Mohamad Azmi, and Azmi Mohd Shariff. "Iron Doped TiO2 Photocatalysts for Environmental Applications: Fundamentals and Progress." Advanced Materials Research 925 (April 2014): 689–93. http://dx.doi.org/10.4028/www.scientific.net/amr.925.689.
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One of the most pervasive problems affecting people throughout the world is inadequate access to clean water and sanitation. Problems with water are expected to grow worse in the coming decades, with water scarcity occurring globally. Many recent studies have been reported on the photodegradation of the organic compounds in industrial wastewater in the presence of TiO2 semiconductor as photocatalyst. Heterogeneous photocatalysts using iron as a dopant metal, so far, have been reported for various environmental applications. This paper highlights the recent advances and applications of Fe-TiO2 photocatalysis for the degradation/photodegradation of various pollutants, alkanolamines and other organic pollutants like phenols and dyes.
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Xiong, Qian, Mi Zhou, and Xin Qian. "The Preparation and Visible Light Photocatalytic Activity of ZnO-TiO2 Nanofibers." Advanced Materials Research 472-475 (February 2012): 3441–44. http://dx.doi.org/10.4028/www.scientific.net/amr.472-475.3441.
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ZnO-TiO2 composite nanofibers were prepared by using the electrospun fibers of PVP/ZnSO4/ Ti(OiPr)4 composite as precursor, and through calcination treatment. The chemical components, structures and morphology were characterized by FT-IR, XRD, SEM, respectively. The photocatalytic activities of the catalysts were investigated by photocatalystic degradation of Rhodamine B under visible-light irradiation. It was found that the ZnO-TiO2 composite nanofibers photocatalyst calcined at 600 °C which was mixed the anatase phase and rutile phase, showed higher photocatalytic activities than those calcined at other two temperatures. This result was expected as a new morphology of photocatalysts to degrade the organic pollutants in the sun.
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Bhatti, Darshana Tushar, and Sachin Prakashbhai Parikh. "Solar Light Induced Photocatalysis for Treatment of High COD Pharmaceutical Effluent with Recyclable Ag-Fe Codoped TiO2: Kinetics of COD Removal." Current World Environment 15, no. 1 (April 24, 2020): 137–50. http://dx.doi.org/10.12944/cwe.15.1.17.
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A wide range of active pharmaceutical ingredients (API) is found in various water streams. These synthetic non-biodegradable organics create trouble in conventional wastewater treatment due to toxicity. There is a strong need to develop substitute technology such as visible light driven photocatalysis with a reusable photocatalyst to completely oxidize these substances into carbon dioxide and water. Sol-gel method was used for synthesis of Fe doped TiO2 and Ag-Fe codoped TiO2 nanoparticles with 0.5 wt% Fe and Ti/Ag molar ratio 30 (Ag-Fe CT 30). The morphology and structure of nanoparticles were studied using various analytical techniques. Ag-Fe CT 30 photocatalyst has exhibited excellent photocatalytic activity compared to commercial TiO2, undoped TiO2 and Fe doped TiO2 nanophotocatalysts under solar and UV irradiation for removal of an antifungal drug intermediate, Difloro triazole acetophenone (DFTA) from water. COD reduction efficiency was highest with Ag-Fe CT 30 under solar and UV irradiation proves the potential of Ag-Fe CT 30 photocatalyst to absorb both UV as well as visible radiations. Ag-Fe CT 30 has shown good stability for 4 runs without much decline in the efficacy. This study provides insights on the solar application of a reusable Ag-Fe CT 30 photocatalyst for the treatment of high strength COD wastewater. Kinetics of COD reduction by photocatalysis has been determined.
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Xu, Shiping, Xiwang Zhang, Jiawei Ng, and Darren Delai Sun. "Preparation and application of TiO2/Al2O3 microspherical photocatalyst for water treatment." Water Supply 9, no. 1 (March 1, 2009): 39–44. http://dx.doi.org/10.2166/ws.2009.074.
Full textAbstract:
Powder photocatalyst is difficult to be separated from treated water, and often contributes to membrane fouling when membrane filtration is employed to conserve photocatalyst, which limits the application of photocatalysis in practice. To solve these problems, TiO2/Al2O3 microspheres consisting of nanosized crystals were fabricated by sol-spraying-calcination method. In humic acid (HA) photodegradation experiments, TiO2/Al2O3 microspheres showed nice photocatalytic activity (removal efficiency nearly 80%), and the activity maintained at high level even after 20 cycles of reuse in durability test, which indicated good mechanical strength of the fabricated microspheres. In continuous operation of hybrid photocatalysis/membrane system, TiO2/Al2O3 microspheres showed excellent pollutant removal ability, and controlled membrane fouling to a great extent.
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Hu, Xiao-Jun, Qi-Zhong Jiang, Xiao-Zhen Liao, Wen-Feng Shangguan, and Zi-Feng Ma. "Visible-Light Photocatalyst of Tetramethoxyphenylporphyrin Sensitized TiO2 Nanotube." Journal of New Materials for Electrochemical Systems 14, no. 4 (May 31, 2011): 247–50. http://dx.doi.org/10.14447/jnmes.v14i4.97.
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This paper investigated the performance of photocatalysts of TiO2 nanotubes sensitized by photosensitizers of tetramethoxyphenylporphyrin(TMPP) for producing H2 from water under visible light. This photocatalyst might have a smaller band gap (2.6 eV). The investigation shows that a photosensitized catalyst combined TiO2 nanotube with TMPP can be used to extend the absorption of solar light region and enhance the efficiency of energy conversion, and the quantity of H2 evolution is 1.427 L m-2h-1g-1. It was a way to apply the dye sensitized TiO2 nanotubes photocatalyst in the visible light for clean energy.
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Bao, Jin Lei, Xiao Yuan Fan, Wei Ping Jin, and Bi Bo Liu. "Preparation of Floating TiO2/EP by Hydrothermal Method." Advanced Materials Research 800 (September 2013): 13–17. http://dx.doi.org/10.4028/www.scientific.net/amr.800.13.
Full textAbstract:
Most of photocatalytic reaction taken place in a slurry type reactor, which is of poor light utilization and difficulty to recycling of photocatalyst. To overcome these drawbacks, a floating photocatalyst (TiO2/EP) was prepred by hrothermal method, in which EP(Expanded Perlite) was used as an substrate. Photocatalysts activity was evaluated under UV light using Rhodamine B as the pollutant model. The effect of heating temperature, heating time and dosage of EP on activity of TiO2/EP were Discussed. The results showed 2h and 200°C were the optimal conditions and the dosage of EP has no significant effect on activity of TiO2/EP. The results of XRD and SEM showed TiO2 is anatase form, well crystallized and dispersed; its particle size is about 100~150nm. This floating photocatalyst can remove about 97.4% rhodamine B(10mg/L) during 90min under UV light. It has broad prospects for engineering applications.
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Xu, Zhi Ying, Xin Gang Wang, Yang Bo Liu, Wei Sheng Ma, and Ze Qin Mo. "Study on Preparation and Decontamination Properties of Hybrid-Photocatalysis Based on Graphene and TiO2." Advanced Materials Research 1092-1093 (March 2015): 988–91. http://dx.doi.org/10.4028/www.scientific.net/amr.1092-1093.988.
Full textAbstract:
The hybrid-photocatalyst was successfully prepared by compositing graphene and TiO2 in this thesis. The properties of the hybrid-photocatalyst was stydited by XRD, SEM. The hotocatalytic activity of the hybrid-photocatalyst was evaluated by decolorization of acid yellow dye solution under visible light irradiation. The result shows that the main phase of the hybrid-photocatalyst is antase TiO2. The effects of different titanium carbon ratio, photocatalysis time, catalyst dosage and pH on the photocatalytic for acid yellow dye are discussed. Under the conditions that titanium carbon ratio 100:50, the photocatalytic time 120 min, catalyst dosing concentration 0.1g / L and the optimum pH 8, the treatment of methyl orange dye is the best.