Journal articles: 'Porous carbon cuboid'

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Karageorgou, Dimitra, Eleni Thomou, Nikolina T. Vourvou, et al. "Antibacterial and Algicidal Effects of Porous Carbon Cuboid Nanoparticles." ACS Omega 4, no. 3 (2019): 4991–5001. http://dx.doi.org/10.1021/acsomega.8b02018.

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Li, Yong, Yanmeng Chi, Shanling Han, Chaojie Zhao, and Yanan Miao. "Pore-throat structure characterization of carbon fiber reinforced resin matrix composites: Employing Micro-CT and Avizo technique." PLOS ONE 16, no. 9 (2021): e0257640. http://dx.doi.org/10.1371/journal.pone.0257640.

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Micro-CT technique poses significant applications in characterizing the microstructure of materials. Based on the CT three-dimensional(3D) reconstruction technology and “Avizo” 3D visualization software, the microscopic pore-throat structure of porous media can be quantitatively characterized. This paper takes the carbon fiber reinforced resin matrix composites as an example to introduce the operation process of “Avizo” in details, which mainly covers the following modules: Volume Edit, Interactive Thresholding, Fill Holes, Mask, Separate Objects and Generate Pore Network Model, then further discuss the difficult problems when the “Avizo” is employed to analyze. The microstructures of carbon fiber reinforced resin matrix composites illustrate that pores in the upper part of sample are dramatically dispersed, and mainly concentrated in the lower part of sample. The porosity of adopted cuboid is 3.6%, accordingly the numbers of pores and throats reach 268 and 7, respectively. The equivalent radius of pores seems mainly distributed in the range of 0.7–0.8μm, accounting for 28.73% of the total pore number. The surface area of pore ranges from 5 to 10μm2, accounting for 14.16% of the total pore number. The pore volume concentrates in the range of 1–20μm3, accounting for 57.46% of the total pore number. In addition, the equivalent radius of throat mainly concentrates in the range of 1–5μm, the overall length of throat is distributed in the range of 37–60μm, and the equivalent area of throat is distributed non-uniformly in the range of 5–75μm2. This work provides a basis for the further investigation of fluid migration mechanism and law in the composite materials by the numerical simulation methodology.

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Sun, Xiaolei, Guang-Ping Hao, Xueyi Lu, et al. "High-defect hydrophilic carbon cuboids anchored with Co/CoO nanoparticles as highly efficient and ultra-stable lithium-ion battery anodes." Journal of Materials Chemistry A 4, no. 26 (2016): 10166–73. http://dx.doi.org/10.1039/c6ta03098j.

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Hao, Guang-Ping, Giovanni Mondin, Zhikun Zheng, et al. "Unusual Ultra-Hydrophilic, Porous Carbon Cuboids for Atmospheric-Water Capture." Angewandte Chemie International Edition 54, no. 6 (2014): 1941–45. http://dx.doi.org/10.1002/anie.201409439.

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Goscianska, Joanna, Aleksander Ejsmont, Anita Kubiak, Dominika Ludowicz, Anna Stasiłowicz, and Judyta Cielecka-Piontek. "Amine-Grafted Mesoporous Carbons as Benzocaine-Delivery Platforms." Materials 14, no. 9 (2021): 2188. http://dx.doi.org/10.3390/ma14092188.

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Smart porous carriers with defined structure and physicochemical properties are required for releasing the therapeutic drug with precise control of delivery time and location in the body. Due to their non-toxicity, ordered structure, and chemical and thermal stability, mesoporous carbons can be considered modern carriers for active pharmaceutical ingredients whose effectiveness needs frequent dosing algorithms. Here, the novel benzocaine delivery systems based on ordered mesoporous carbons of the cubic structure were obtained with the use of a hard template method and functionalization with amine groups at 40 °C for 8 h. It has been shown that amine grafting strongly modifies the surface chemistry and textural parameters of carbons. All samples indicated good sorption ability towards benzocaine, with evident improvement following the functionalization with the amine groups. The sorption capacity and drug release kinetics were strongly affected by the porosity of carbon carriers and the surface functional groups. The smallest amount of benzocaine (~12%) was released from pristine mesoporous carbon, which could be correlated with strong API–carrier interactions. Faster and more efficient release of the drug was observed in the case of triethylenetetramine modified carbon (~62%). All benzocaine delivery platforms based on amine-grafted mesoporous carbons revealed high permeability through the artificial membrane.

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Wang, Dengxu, Wenyan Yang, Shengyu Feng, and Hongzhi Liu. "Constructing hybrid porous polymers from cubic octavinylsilsequioxane and planar halogenated benzene." Polym. Chem. 5, no. 11 (2014): 3634–42. http://dx.doi.org/10.1039/c3py01688a.

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Hybrid porous polymers derived from cubic octavinylsilsequioxane and planar halogenated benzene monomers exhibit high thermal stability, tunable porosities and potential applications in carbon dioxide storage.

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Li, Da, Fubo Tian, Binhua Chu, et al. "Cubic C96: a novel carbon allotrope with a porous nanocube network." Journal of Materials Chemistry A 3, no. 19 (2015): 10448–52. http://dx.doi.org/10.1039/c5ta01045d.

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Liu, Guixia, and Guangyan Hong. "Synthesis and Photoluminescence of Y2O3:RE3+ (RE = Eu, Tb, Dy) Porous Nanotubes Templated by Carbon Nanotubes." Journal of Nanoscience and Nanotechnology 6, no. 1 (2006): 120–24. http://dx.doi.org/10.1166/jnn.2006.17915.

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Y2O3:RE3+ (RE = Eu, Tb, Dy) porous nanotubes were first synthesized using carbon nanotubes as template. The morphology of the coated precursors and porous Y2O3:Eu3+ nanotubes was determined by scanning electron Microscopy (SEM) and transmission electron microscopy (TEM). It was found that the coating of precursors on carbon nanotubes (CNTs) is continuous and the thickness is about 15 nm, after calcinated, the Y2O3:Eu3+ nanotubes are porous with the diameter size in the range of 50–80 nm and the length in micrometer scale. X-ray diffraction (XRD) patterns confirmed that the samples are cubic phase Y2O3 and the photoluminescence studies showed that the porous rare earth ions doped nanotubes possess characteristic emission of Eu3+, Tb3+, and Dy3+. This method may also provide a novel approach to produce other inorganic porous nanotubes used in catalyst and sensors.

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Zhang, Anfeng, Keke Hou, Haiyang Duan, Wei Tan, Chunshan Song, and Xinwen Guo. "Zirconium-promoted hydrothermal synthesis of hierarchical porous carbons with ordered cubic mesostructures under acidic aqueous conditions." RSC Advances 6, no. 6 (2016): 4343–53. http://dx.doi.org/10.1039/c5ra19416d.

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Hierarchical porous carbons with ordered cubic mesostructure (Im3m) were synthesized under acidic aqueous conditions by a zirconium-promoted hydrothermal method, F127 as template, pre-synthesized resol as precursor, and hydrochloric acid as catalyst.

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Gao, Dawei, Lili Wang, Xin Xia, et al. "Preparation and Characterization of porous Carbon/Nickel Nanofibers for Supercapacitor." Journal of Engineered Fibers and Fabrics 8, no. 4 (2013): 155892501300800. http://dx.doi.org/10.1177/155892501300800405.

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Two polymer solutions of polyacrylonitrile, polyvinyl pyrrolidone, and Ni(CH3COOH)2 in dimethylformamide were electrospun into ternary composite nanofibers, followed by stabilization and carbonization processes to obtain porous carbon/nickel composite nanofibers with diameters of 100–200 nm. The study revealed that carbon/nickel composite nanofibers were successfully prepared, which allowed nickel particles with diameters of 20–70 nm to be uniformly distributed in the carbon nanofibers. It was also observed that the fibrous structures with particles embedded formed and the fibers broke into shorter fibers after sintering. X-ray diffraction indicated that embedded particles crystallized with the face centered cubic structure. The Brunauer-Emmett-Teller analysis revealed that carbon/nickel composite nanofibers with meso-pores possessed larger specific surface area than that of carbon nanofibers. The specific capacitance of the composite nanofiber electrode was as high as 103.8 F/g and showed stable cyclicity (73.8%).

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Li, Zhen, Fan Bu, Junjie Wei, et al. "Boosting the energy storage densities of supercapacitors by incorporating N-doped graphene quantum dots into cubic porous carbon." Nanoscale 10, no. 48 (2018): 22871–83. http://dx.doi.org/10.1039/c8nr06986g.

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Hierarchical N-doped porous carbon has been prepared by assembling N-doped graphene quantum dots (N-GQDs) onto a carbonized metal–organic framework (cMOF-5) and used as an electrode material for supercapacitors.

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Gao, Da Wei, Qu Fu Wei, Chun Xia Wang, et al. "Preparation and Characterization of Porous Carbon/Nickle Nanofibers by Electrospinning." Advanced Materials Research 853 (December 2013): 101–4. http://dx.doi.org/10.4028/www.scientific.net/amr.853.101.

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By employing the electrospinning technique and subsequent carbonization processes, porous carbon/nickle (C/Ni) composite nanofibers with diameters of 100-200 nm were successfully prepared. Two polymer solutions of polyacrylonitrile (PAN), polyvinyl pyrrolidone (PVP), and Ni (CH3COOH)2(Ni (OAc)2) were used as C/Ni composite nanofiber precursors. The study revealed that C/Ni composite nanofibers were successfully prepared and nickle particles with diameters of 20-70 nm were uniformly scattered in the carbon nanofibers. It was also observed that the fiber with clear fibrous morphology with particles broke into shorter fibers after sinter. X-ray diffraction (XRD) showed that these particles crystallized with the face centered cubic (FCC) structure. The Brunauer-Emmett-Teller (BET) analysis indicated that C/Ni composites nanofibers with meso-pores possessed larger specific surface area than that of carbon nanofibers.

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Hammud, Hassan H., Nusaybah Alotaibi, Nasreen Al Otaibi, et al. "Hierarchical Porous Carbon Cobalt Nanocomposites-Based Sensor for Fructose." Chemosensors 9, no. 1 (2020): 6. http://dx.doi.org/10.3390/chemosensors9010006.

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3D hierarchical graphitic carbon nanowalls encapsulating cobalt nanoparticles HPC-Co were prepared in high yield from solid-state pyrolysis of cobalt 2,2′-bipyridine chloride complex. Annealing of HPC-Co in air gave HPC-CoO, which consists of a mixture of crystallite Co3O4 nanospheres and nanorods bursting out of mesoporous carbon. Both nanocomposites were fully characterized using SEM, TEM, BET, and powder X-ray diffraction. The elemental composition of both nanocomposites examined using SEM elemental mapping and TEM elemental mapping supports the successful doping of nitrogen. The powder X-ray diffraction studies supported the formation of hexagonal cobalt in HPC-Co, and cubic crystalline Co3O4 with cubic cobalt in HPC-CoO. HPC-Co and HPC-CoO can be used as a modified carbon electrode in cyclic voltammetry experiments for the detection of fructose with limit of detection LOD 0.5 mM. However, the single-frequency impedimetric method has a wider dynamic range of 8.0–53.0 mM and a sensitivity of 24.87 Ω mM−1 for the electrode modified with HPC-Co and 8.0–87.6 mM and a sensitivity of 1.988 Ω mM−1 for the electrode modified with HPC-CoO. The LOD values are 3 and 4 mM, respectively. The effect of interference increases in the following order: ascorbic acid, ethanol, urea, and glucose. A simple method was used with negligible interference from glucose to measure the percentage of fructose in a corn syrup sample with an HPC-CoO electrode. A specific capacitance of 47.0 F/g with 76.6% retentivity was achieved for HPC-Co and 28.2 F/g with 87.9% for HPC-CoO for 3000 charge–discharge cycles. Thus, (1) has better sensitivity and specific capacitance than (2), because (1) has a higher surface area and less agglomerated cobalt nanoparticles than (2).

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Chatzikonstantinou, Gkantzou, Thomou та ін. "Enzymatic Conversion of Oleuropein to Hydroxytyrosol Using Immobilized β-Glucosidase on Porous Carbon Cuboids". Nanomaterials 9, № 8 (2019): 1166. http://dx.doi.org/10.3390/nano9081166.

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In the present study, we developed novel β-glucosidase-based nano-biocatalysts for the bioconversion of oleuropein to hydroxytyrosol. Using non-covalent or covalent immobilization approaches, β-glucosidases from almonds and Thermotoga maritima were attached for the first time on oxidized and non-oxidized porous carbon cuboids (PCC). Various methods were used for the characterization of the bio-nanoconjugates, such as Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and fluorescence spectroscopy. The oxidation state of the nanο-support and the immobilization procedure play a key role for the immobilization efficiency or the catalytic activity of the immobilized β-glucosidases. The nano-biocatalysts were successfully used for the hydrolysis of oleuropein, which leads to the formation of its bioactive derivative, hydroxytyrosol (up to 2.4 g L−1), which is a phenolic compound with numerous health benefits. The bio-nanoconjugates exhibited high thermal and operational stability (up to 240 hours of repeated use), which indicated that they are efficient tools for various bio-transformations.

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Li, Chengming, Bicheng Huang, Chengxian Li, Xiao Chen, and Yaqin Huang. "In situ formation of nanoscale zero-value iron on fish-scale-based porous carbon for Cr(VI) adsorption." Water Science and Technology 73, no. 9 (2016): 2237–43. http://dx.doi.org/10.2166/wst.2016.077.

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Magnetic carbon materials that have nanoscale zero-valent iron (nZVI) supported on fish scale based hierarchical lamellar porous carbon (FHLC) is reported in this study. The nZVI on FHLC was in the form of body-centered-cubic iron (Fe) crystal. Although it was demonstrated that the specific surface area (SBET), total pore volume (Vt) and micropore volume (Vm) of the FHLC decreased with the increase of Fe contents, a certain amount of addition of iron nanoparticles on FHLC enhances the Cr(VI) adsorption properties. The as-prepared material shows faster adsorption rate and higher maximum adsorption capacity (357.14 mg/g) compared to bare FHLC (344.83 mg/g). In addition, this magnetic carbon material exhibits a high saturated magnetization (16.49 emu/g). It is indicated that the as-prepared carbon material not only can be used to remove Cr(VI) efficiently but also shows excellent magnetic separation performance from wastewater.

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Panda, Atanu, Euisoo Kim, Yong Choi, Jihyun Lee, Sada Venkateswarlu, and Minyoung Yoon. "Phase Controlled Synthesis of Pt Doped Co Nanoparticle Composites Using a Metal-Organic Framework for Fischer–Tropsch Catalysis." Catalysts 9, no. 2 (2019): 156. http://dx.doi.org/10.3390/catal9020156.

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Recently, metal nanoparticles embedded in porous carbon composite materials have been playing a significant role in a variety of fields as catalyst supports, sensors, absorbents, and in energy storage. Porous carbon composite materials can be prepared using various synthetic methods; recent efforts provide a facile way to prepare the composites from metal-organic frameworks (MOFs) by pyrolysis. However, it is usually difficult to control the phase of metal or metal oxides during the synthetic process. Among many types of MOF, recently, cobalt-based MOFs have attracted attention due to their unique catalytic and magnetic properties. Herein, we report the synthesis of a Pt doped cobalt based MOF, which is subsequently converted into cobalt nanoparticle-embedded porous carbon composites (Pt@Co/C) via pyrolysis. Interestingly, the phase of the cobalt metal nanoparticles (face centered cubic (FCC) or hexagonal closest packing (HCP)) can be controlled by tuning the synthetic conditions, including the temperature, duration time, and dosage of the reducing agent (NaBH4). The Pt doped Co/C was characterized using various techniques including PXRD (powder X-ray diffraction), XPS (X-ray photoelectron spectroscopy), gas sorption analysis, TEM (transmission electron microscopy), and SEM (scanning electron microscopy). The composite was applied as a phase transfer catalyst (PTC). The Fischer-Tropsch catalytic activity of the Pt@Co/C (10:1:2.4) composite shows 35% CO conversion under a very low pressure of syngas (1 MPa). This is one of the best reported conversion rates at low pressure. The 35% CO conversion leads to the generation of various hydrocarbons (C1, C2–C4, C5, and waxes). This catalyst may also prove useful for energy and environmental applications.

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Calvino, M., A. Trejo, M. I. Iturrios, M. C. Crisóstomo, Eliel Carvajal, and M. Cruz-Irisson. "DFT Study of the Electronic Structure of Cubic-SiC Nanopores with a C-Terminated Surface." Journal of Nanomaterials 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/471351.

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A study of the dependence of the electronic structure and energetic stability on the chemical surface passivation of cubic porous silicon carbide (pSiC) was performed using density functional theory (DFT) and the supercell technique. The pores were modeled by removing atoms in the [001] direction to produce a surface chemistry composed of only carbon atoms (C-phase). Changes in the electronic states of the porous structures were studied by using different passivation schemes: one with hydrogen (H) atoms and the others gradually replacing pairs of H atoms with oxygen (O) atoms, fluorine (F) atoms, and hydroxide (OH) radicals. The results indicate that the band gap behavior of the C-phase pSiC depends on the number of passivation agents (other than H) per supercell. The band gap decreased with an increasing number of F, O, or OH radical groups. Furthermore, the influence of the passivation of the pSiC on its surface relaxation and the differences in such parameters as bond lengths, bond angles, and cell volume are compared between all surfaces. The results indicate the possibility of nanostructure band gap engineering based on SiC via surface passivation agents.

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Sun, Hai Tao, Sa Zhang, Hui Yong Deng, Kai Bo Cui, and Fang Zhao. "Microwave Absorption Properties of Porous Co/C Nanofibers Synthesized by Electrospinning." Materials Science Forum 975 (January 2020): 133–38. http://dx.doi.org/10.4028/www.scientific.net/msf.975.133.

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Porous Co/C composite nanofibers were fabricated by combination of electrospinning method and polymer blend. The phase composition, microstructure and electromagnetic characteristics of them were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and vector network analyzer (VNA), and their microwave absorption performances were studied. The results indicate that nanofibers were composited by amorphous carbon and face-centered cubic structured Co nanoparticle after sintering. The addition of PMMA is a key factor of nanofibers morphology and the aperture was improved with the increase of PMMA. When the thickness is 2.0 mm, the samples exhibit the best microwave absorption performance. Their effective absorpt ion bandwidths (RL < 10 dB) are 6.3 GHz, 6.2 GHz and 6.1 GHz, and it’s obviously superior to ordinary morphology nanofibers.

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Javed, Muhammad Sufyan, Hidayat Ullah Shah, Nusrat Shaheen, et al. "High energy density hybrid supercapacitor based on 3D mesoporous cuboidal Mn2O3 and MOF-derived porous carbon polyhedrons." Electrochimica Acta 282 (August 2018): 1–9. http://dx.doi.org/10.1016/j.electacta.2018.06.009.

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Imperial, James Francis L., and Rinlee Butch M. Cervera. "Synthesis and Characterization of Porous NiO/YSZ Electrode Materials Using Different Pore Formers." Materials Science Forum 917 (March 2018): 83–87. http://dx.doi.org/10.4028/www.scientific.net/msf.917.83.

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Solid oxide electrolysis cell (SOEC) cathodes require a good porosity and a fine microstructure in order to maximize the triple phase boundary (TPB) between electronic conductor, ionic conductor and the gas phase involved in the reaction. Nickel oxide and yttria stabilized zirconia (NiO/YSZ) composite, one of the most desired candidates for SOEC cathode material, is synthesized via the glycine-nitrate combustion process and mixed with corn starch and carbon black pore formers in order to observe how they modify its microstructure and porosity. XRD spectra indicate a distinct cubic phases of both NiO and YSZ. SEM micrographs were able to confirm that the addition of selected pore formers lead to an increase in porosities. Apparent and relative density measurements show that corn starch pore former produces the lowest density among the sintered pellets. EIS measurements revealed that samples with lower density also showed lower total conductivity.

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Khand, Aftab A., Saeed A. Lakho, Aneela Tahira, et al. "Facile Electrochemical Determination of Methotrexate (MTX) Using Glassy Carbon Electrode-Modified with Electronically Disordered NiO Nanostructures." Nanomaterials 11, no. 5 (2021): 1266. http://dx.doi.org/10.3390/nano11051266.

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Recently, the oxidative behavior of methotrexate (MTX) anticancer drug is highly demanded, due to its side effects on healthy cells, despite being a very challenging task. In this study, we have prepared porous NiO material using sodium sulfate as an electronic disorder reagent by hydrothermal method and found it highly sensitive and selective for the oxidation of MTX. The synthesized NiO nanostructures were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD) techniques. These physical characterizations delineated the porous morphology and cubic crystalline phase of NiO. Different electrochemical approaches have been utilized to determine the MTX concentrations in 0.04 M Britton–Robinson buffer (BRB) at pH 2 using glassy carbon electrode (GCE)-modified with electronically disordered NiO nanostructures. The linear range for MTX using cyclic voltammetry (CV) was found to be from 5 to 30 nM, and the limit of detection (LOD) and limit of quantification (LOQ) were 1.46 nM and 4.86 nM, respectively, whereas the linear range obtained via linear sweep voltammetry (LSV) was estimated as 15–90 nM with LOD and LOQ of 0.819 nM and 2.713 nM, respectively. Additionally, amperometric studies revealed a linear range from 10 to70 nM with LOD and LOQ of 0.1 nM and 1.3 nM, respectively. Importantly, MTX was successfully monitored in pharmaceutical products using the standard recovery method. Thus, the proposed approach for the synthesis of active metal oxide materials could be sued for the determination of other anticancer drugs in real samples and other biomedical applications.

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Furuuchi, Natsumi, Rekha Shrestha, Yuji Yamashita, Tetsuji Hirao, Katsuhiko Ariga, and Lok Shrestha. "Self-Assembled Fullerene Crystals as Excellent Aromatic Vapor Sensors." Sensors 19, no. 2 (2019): 267. http://dx.doi.org/10.3390/s19020267.

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Here we report the aromatic vapor sensing performance of bitter melon shaped nanoporous fullerene C60 crystals that are self-assembled at a liquid-liquid interface between isopropyl alcohol and C60 solution in dodecylbenzene at 25 °C. Average length and center diameter of the crystals were ca. 10 μm and ~2 μm, respectively. Powder X-ray diffraction pattern (pXRD) confirmed a face-centered cubic (fcc) structure with cell dimension ca. a = 1.4272 nm, and V = 2.907 nm3, which is similar to that of the pristine fullerene C60. Transmission electron microscopy (TEM) confirmed the presence of a nanoporous structure. Quartz crystal microbalance (QCM) results showed that the bitter melon shaped nanoporous C60 performs as an excellent sensing system, particularly for aromatic vapors, due to their easy diffusion through the porous architecture and strong π–π interactions with the sp2-carbon.

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Lehman, R. Michael, Frederick S. Colwell, and Greg A. Bala. "Attached and Unattached Microbial Communities in a Simulated Basalt Aquifer under Fracture- and Porous-Flow Conditions." Applied and Environmental Microbiology 67, no. 6 (2001): 2799–809. http://dx.doi.org/10.1128/aem.67.6.2799-2809.2001.

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ABSTRACT Bench scale column studies were used to examine the partitioning of microorganisms between groundwater and a geologic medium and to examine the effect of hydrogeology (i.e., porous- versus fracture-flow) on organism partitioning. Replicated columns were constructed with intact basalt core segments that contained natural fractures and with the same basalt crushed into particles. The columns were perfused with groundwater, and upon reaching a steady state, the columns were sacrificed and the attached and unattached communities were analyzed by multiple approaches. The analyses included the total number of cells, the phylogenetic affiliation of the cells (i.e., the α, β, and γ subclasses of the class Proteobacteria and gram positives with high G+C DNA content) by fluorescent in situ hybridization (FISH), number and taxonomic affiliation by fatty acid methyl ester profiles of culturable heterotrophs, most-probable-number estimates of methanotrophs and phenol oxidizers, and whole-community sole carbon source utilization patterns from Biolog GN microplates. In the packed columns, about 99% of the total biomass (per cubic centimeter of porous medium) was attached to the geologic medium. Lack of equitable units precluded a comparison of attached and unattached biomasses in the fractured columns where the attached biomass was expressed per unit of surface area. Compositional differences in the attached and unattached communities were evidenced by (i) the recovery ofPseudomonas stutzeri, an Enterococcus sp., andBacillus psychrophilus from the groundwater and not from the basalt, (ii) differences between community carbon source utilization patterns, and (iii) the relative abundances of different phylogenetic groups estimated by FISH in both column types. In the packed columns, attached communities were depleted of members of the α- and β-Proteobacteria subclasses in comparison to those in the corresponding groundwater. In the fractured columns, attached communities were enriched in gram-positive Bacteriaand γ-Proteobacteria and depleted of β-Proteobacteria, in comparison to those in the corresponding groundwater. Segregation of populations and their activities, possibly modified by attachment to geologic media, may influence contaminant fate and transport in the subsurface and impact other in situ applications.

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Ndiaye, Ndeye M., Ndeye F. Sylla, Balla D. Ngom, et al. "Nitridation Temperature Effect on Carbon Vanadium Oxynitrides for a Symmetric Supercapacitor." Nanomaterials 9, no. 12 (2019): 1762. http://dx.doi.org/10.3390/nano9121762.

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In this work, porous carbon-vanadium oxynitride (C-V2NO) nanostructures were obtained at different nitridation temperature of 700, 800 and 900 °C using a thermal decomposition process. The X-ray diffraction (XRD) pattern of all the nanomaterials showed a C-V2NO single-phase cubic structure. The C-V2NO obtained at 700 °C had a low surface area (91.6 m2 g−1), a moderate degree of graphitization, and a broader pore size distribution. The C-V2NO obtained at 800 °C displayed an interconnected network with higher surface area (121.6 m2 g−1) and a narrower pore size distribution. In contrast, at 900 °C, the C-V2NO displayed a disintegrated network and a decrease in the surface area (113 m2 g−1). All the synthesized C-V2NO yielded mesoporous oxynitride nanostructures which were evaluated in three-electrode configuration using 6 M KOH aqueous electrolyte as a function of temperature. The C-V2NO@800 °C electrode gave the highest electrochemical performance as compared to its counterparts due to its superior properties. These results indicate that the nitridation temperature not only influences the morphology, structure and surface area of the C-V2NO but also their electrochemical performance. Additionally, a symmetric device fabricated from the C-V2NO@800 °C displayed specific energy and power of 38 W h kg−1 and 764 W kg−1, respectively, at 1 A g−1 in a wide operating voltage of 1.8 V. In terms of stability, it achieved 84.7% as capacity retention up to 10,000 cycles which was confirmed through the floating/aging measurement for up to 100 h at 10 A g−1. This symmetric capacitor is promising for practical applications due to the rapid and easy preparation of the carbon-vanadium oxynitride materials.

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Rosli, A. R., S. H. Loh, and F. Yusoff. "Synthesis and Characterization of Magnetic Fe3O4/Reduced Graphene Oxide and its Application in Determination of Dopamine." Asian Journal of Chemistry 31, no. 12 (2019): 2785–92. http://dx.doi.org/10.14233/ajchem.2019.22213.

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An electrochemical sensor to determine dopamine in the human body was fabricated based on modified iron oxide/reduced graphene oxide/glassy carbon electrode (Fe3O4/r-GO/GCE). Determination of dopamine is significance nowadays as the abnormal level may cause various mental health diseases as well as Parkinson’s disease. The Fe3O4/r-GO nanocomposite was synthesized via Hummer’s method with a slight modification and characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Brunauer Emmett-Teller (BET). The presence of Fe3O4 onto the surface of r-GO was confirmed by SEM analysis which shows the bulky porous sponge-like structure attached to an exfoliated sheet of r-GO. FTIR analysis proved the presence of the functional group in existing composites via oxidation process of graphene oxide and reduction process of reduced graphene oxide while the crystalline form of Fe3O4/r-GO was determined using XRD analysis. The diffraction peaks index to the cubic phase was noticeable indicating the successful crystallization of the composites. The catalytic activity of bare GCE and modified GCE (Fe3O4/r-GO/ GCE) were observed using electrochemical characterization of cyclic voltammetry, differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) with optimum pH of 7, a concentration of 100 μM, and the scan rate of 250 mV s-1. The observed DPV response linearly depends on dopamine concentration in the range of 20-100 μM, with correlation coefficients of 0.9876. The detection limit obtained for the real sample analysis was found to be 0.569 μM while the limit of quantitation was 1.897 μM. The percentage of recovery, repeatability and reproducibility was 113, 82.81 and 7.19 %, respectively.

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Duangsa, Kornrawit, Apishok Tangtrakarn, Charusporn Mongkolkachit, Pavadee Aungkavattana, and Klitsada Moolsarn. "The Effect of Tartaric Acid and Citric Acid as a Complexing Agent on Defect Structure and Conductivity of Copper Samarium Co-Doped Ceria Prepared by a Sol-Gel Auto-Combustion Method." Advances in Materials Science and Engineering 2021 (July 22, 2021): 1–23. http://dx.doi.org/10.1155/2021/5592437.

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Copper samarium co-doped ceria (CSDC) (Cu0.01Sm0.19Ce0.80O2−δ) nanoparticles were synthesized via a sol-gel auto-combustion of metal nitrates without a complexing agent (DI) and with tartaric acid (TA) or citric acid (CA). The solid oxide formation of CSDC/DI corresponds to the endothermic stage, whereas that of CSDC/TA and CSDC/CA matches the exothermic stage caused by the decomposition of the metal cross-linking and carbon combustion. The cross-linking occurs more extensively in the CA case as more heat is released in CA than in the TA route. The as-synthesized morphology of CSDC/DI reveals both layered structures and small agglomerated particles, whereas CSDC/TA and CSDC/CA show dense xerogel and porous xerogel, respectively. The cubic fluorite structure for calcined CSDCs was confirmed by XRD. From Raman analysis, calcined CSDC/CA has the lowest amount of copper segregation and the highest relative total oxygen vacancy concentration [ V O • • ]total, whereas calcined CSDC/DI has the highest amount of copper segregation and the lowest [ V O • • ]total. For all samples, copper segregation promotes densification, albeit to varying degrees. The relative densities of CSDC/DI, CSDC/TA, and CSDC/CA pellets are 82.8 ± 2.4%, 95.5 ± 1.8%, and 97.8 ± 0.9%, respectively. The sintered CSDC/DI has the lowest density because some copper segregates and liquid copper in interparticle spaces could evaporate earlier than samples containing a complexing agent, whereas sintered CSDC/CA has the highest density because Cu could slowly diffuse from the Cu-Sm-Ce solid solution to grain boundary regions and then precipitate as CuO. The specific grain boundary conductivity is predominantly influenced by CuO along grain boundaries, which reduces specific grain boundary conductivity and increases the enthalpy of association (ΔHa) at 250–350°C; however, it rarely impacts total grain boundary conductivity at temperatures higher than 400°C. CSDC/CA has slightly higher total conductivity than CSDC/TA despite having more CuO segregation because it has higher density and V O • • .

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Bensadon, E. O., P. A. P. Nascente, L. O. S. Bulhões, and E. C. Pereira. "Surface Characterization of Calcium-Stabilized Zirconia Film by X-Ray Photoelectron Spectroscopy." MRS Proceedings 495 (1997). http://dx.doi.org/10.1557/proc-495-395.

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ABSTRACTA new methodology was developed to stabilized zirconia films at room temperature. The zirconium oxide films were prepared electrochemically by anodic oxidation of metallic zirconium at constant curcent density. X-ray diffraction (XRD) revealed the partial stabilization of the cubic phase in the ZrO2 films obtained in the presence of calcium. On the other hand, the films obtained in H3PO4 presented monoclinic phase. Scanning electron microscopy (SEM) showed that the oxide films obtained in calcium medium were porous, while the films obtained in H3PO4 were compact. X-ray photoelectron spectroscopy (XPS) identified ZrO2 and the intercalation of Na, N, P and CaO, as well as adventitious carbon. Using depth profiling, we observed that the concentrations of ZrO2, P and CaO increased with sputtering time.

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Chen, Shouhui, Rihui Zhou, Yaqin Chen, et al. "Carbon-covered Fe3O4 hollow cubic hierarchical porous composite as the anode material for lithium-ion batteries." Journal of Nanoparticle Research 19, no. 4 (2017). http://dx.doi.org/10.1007/s11051-017-3794-x.

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Suslick, Kenneth S., Taeghwan Hyeon, Mingming Fang, and Andrzej A. Cichowlas. "Sonochemical Synthesis and Catalytic Properties of Nanostructured Molybdenum Carbide." MRS Proceedings 351 (1994). http://dx.doi.org/10.1557/proc-351-201.

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ABSTRACTMolybdenum hexacarbonyl in hexadecane was irradiated with high intensity ultrasound under argon at 90°C to yield face centered cubic molybdenum carbide, Mo2C. After thermal treatment, oxygen and excess carbon were removed to give stoichiometric Mo2C. SEM micrographs showed that the surface was extremely porous. TEM micrographs showed that the solid was an aggregate of particles with diameters of ≈ 2 nm. This material has a very high surface area, 188 m2/g as determined by BET gas adsorption. Catalytic studies have been conducted on the dehydrogenation of cyclohexane and the hydrogenolysis of ethane. The sonochemically prepared Mo2C shows good catalytic activity for the dehydrogenation of cyclohexane with 100% selectivity for formation of benzene without hydrogenolysis to methane. The material revealed poor catalytic activity for the hydrogenolysis of ethane.

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G, Rajeshwari, and Chandrappa Gujjarahalli thimmanna. "Solution combustion synthesis, characterization, photocatalytic activity and electrochemical studies of yttrium stabilized zirconia ( Zr0.72 Y0.28 O1.862 ) nanopowder." Current Nanomaterials 06 (September 9, 2021). http://dx.doi.org/10.2174/2405461506666210909130945.

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Background: In our work, we effectively synthesized Yttrium stabilized zirconia (YSZ) Zr0.72 Y0.28 O1.862 nanopowder by solution combustion method using yttrium nitrate (Y(NO3)3.6H2O), zirconyl nitrate (ZrO(NO3)2.XH2O) as oxidizers and ethylenediamine tetra acetic acid (EDTA) as a fuel. The as-synthesized nanopowder was characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Breauner Emmet Teller (BET) surface area, UV-Vis diffuse reflectance spectrum (UV-DRS) and photoluminescence (PL) technique. The phase formation of YSZ nanopowder was analysed by Powder X-ray diffraction (PXRD) revealed the formation of pure cubic phase of YSZ (Zr0.72 Y0.28 O1.862) nanopowder and the crystallite size of 15.4 nm was calculated by using Scherrer’s formula. Methods: The porous morphology of the product was observed by SEM images. The relatively larger surface area of 87.17 m2g–1 was measured by BET surface area. TEM analysis revealed uniform particle size distribution with average particle sizes varying in the range of 20-100 nm. The UV-Vis DRS spectrum was used to calculate the absorption wavelength (339 nm) and the corresponding band gap (3.72 eV) using Tauc plot. The photoluminescence spectrum of YSZ nanopowder showed an emission peak at 339 nm. Results: The photodegradation (decolourisation) of methylene blue (MB) dye was increased from 75-90% with increase in the concentration of YSZ photocatalyst from 100 mg to 400 mg due to availability of OH radicals in the presence of UV radiation. Conclusion : The electrochemical studies using cyclic voltammetry reveal a substantial increase in current density of YSZ electrode from 0.0001A to 0.0005A when compared with bare carbon electrode and the instantaneous rise in redox current for the YSZ electrodes from 0.0001A to 0.0005A with increasing scan rate from 10 mVs-1 to 90 mVs-1.

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Journal articles on the topic 'Porous carbon cuboid'

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