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Journal articles on the topic 'Supported catalyst'
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1
Miceli, Mariachiara, Patrizia Frontera, Anastasia Macario, and Angela Malara. "Recovery/Reuse of Heterogeneous Supported Spent Catalysts." Catalysts 11, no. 5 (2021): 591. http://dx.doi.org/10.3390/catal11050591.
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The rapid separation and efficient recycling of catalysts after a catalytic reaction are considered important requirements along with the high catalytic performances. In this view, although heterogeneous catalysis is generally less efficient if compared to the homogeneous type, it is generally preferred since it benefits from the easy recovery of the catalyst. Recycling of heterogeneous catalysts using traditional methods of separation such as extraction, filtration, vacuum distillation, or centrifugation is tedious and time-consuming. They are uneconomic processes and, hence, they cannot be carried out in the industrial scale. For these limitations, today, the research is devoted to the development of new methods that allow a good separation and recycling of catalysts. The separation process should follow a procedure economically and technically feasible with a minimal loss of the solid catalyst. The aim of this work is to provide an overview about the current trends in the methods of separation/recycling used in the heterogeneous catalysis.
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Hao, Panpan, Mingjiang Xie, Shanyong Chen, et al. "Surrounded catalysts prepared by ion-exchange inverse loading." Science Advances 6, no. 20 (2020): eaay7031. http://dx.doi.org/10.1126/sciadv.aay7031.
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The supported catalyst featuring highly dispersed active phase on support is the most important kind of industrial catalyst. Extensive research has demonstrated the critical role (in catalysis) of the interfacial interaction/perimeter sites between the active phase and support. However, the supported catalyst prepared by traditional methods generally presents low interface density because of limit contact area. Here, an ion-exchange inverse loading (IEIL) method has been developed, in which the precursor of support is controllably deposited onto the precursor of active phase by ion-exchange reaction, leading to an active core surrounded (by support) catalyst with various structures. The unique surrounded structure presents not only high interface density and mutually changed interface but also high stability due to the physical isolation of active phase, revealing superior catalytic performances to the traditional supported catalysts, suggesting the great potential of this new surrounded catalyst as the upgrade of supported catalyst in heterogeneous catalysis.
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Post, M. F. M., and P. W. Lednor. "Catalyst supports and supported catalysts." Applied Catalysis 45, no. 2 (1988): 372–74. http://dx.doi.org/10.1016/s0166-9834(00)83057-2.
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Sankarshana, T., J. Soujanya, and A. Anil Kumar. "Triphase Catalysis Using Silica Gel as Support." International Journal of Chemical Reactor Engineering 11, no. 1 (2013): 347–52. http://dx.doi.org/10.1515/ijcre-2013-0007.
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Abstract The oxidation reaction of 2-ethyl-1-hexanol with potassium permanganate in the presence and absence of silica-gel-supported phase-transfer catalyst (PTC) in triphasic conditions was studied. In a batch reactor, the performance of the solid-supported catalysts was compared with unsupported catalyst and without the catalyst. The effect of speed of agitation, catalyst concentration, potassium permanganate concentration and temperature on reaction rate was studied. The reaction is found to be in the kinetic regime. The rate of reaction with the catalyst immobilised on the silica gel was less compared to the catalyst without immobilisation. Triphase catalysis with supported PTCs has potential applications in the continuous quest for greener industrial practices.
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Torres-Aldaco, Alejandro, Jessica Torres-Cervantes, Raúl Lugo-Leyte та Helen Lugo-Méndez. "Potassium catalysts supported on γ-Al2O3 to produce biodiesel". Renewable Energy, Biomass & Sustainability 3, № 2 (2022): 25–35. http://dx.doi.org/10.56845/rebs.v3i2.49.
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 Biodiesel production is carried out through homogeneous catalysis that forms complex reaction mixtures and has high operating costs. The aim of this work is to synthesize basic, active and selective heterogeneous catalysts for the transesterification reaction with vegetable oils employing g-alumina as support and potassium as active species. The catalysts were characterized by X-ray diffraction and infrared spectroscopy. The amount of catalyst used in the reaction was scanned in a range of 1-10% w, obtaining a maximum conversion of 85% at 55 °C with 6.5% w/w of catalyst with respect to the reagent load and with a methanol-oil molar ratio of 6: 1, reaching equilibrium conversion at six hours. The catalysts were tested at 40, 45, 50 and 55 °C in the transesterification reaction using refined sunflower oil and anhydrous methanol as reagents in a 6: 1 ratio. The 40% K catalyst obtained the best conversion at 55 °C with 85% and showed a selectivity of 45%.
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Latos, Piotr, Anna Wolny, and Anna Chrobok. "Supported Ionic Liquid Phase Catalysts Dedicated for Continuous Flow Synthesis." Materials 16, no. 5 (2023): 2106. http://dx.doi.org/10.3390/ma16052106.
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Heterogeneous catalysis, although known for over a century, is constantly improved and plays a key role in solving the present problems in chemical technology. Thanks to the development of modern materials engineering, solid supports for catalytic phases having a highly developed surface are available. Recently, continuous-flow synthesis started to be a key technology in the synthesis of high added value chemicals. These processes are more efficient, sustainable, safer and cheaper to operate. The most promising is the use of heterogeneous catalyst with column-type fixed-bed reactors. The advantages of the use of heterogeneous catalyst in continuous flow reactors are the physical separation of product and catalyst, as well as the reduction in inactivation and loss of the catalyst. However, the state-of-the-art use of heterogeneous catalysts in flow systems compared to homogenous ones remains still open. The lifetime of heterogeneous catalysts remains a significant hurdle to realise sustainable flow synthesis. The goal of this review article was to present a state of knowledge concerning the application of Supported Ionic Liquid Phase (SILP) catalysts dedicated for continuous flow synthesis.
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Trigoura, Leslie, Yalan Xing, and Bhanu P. S. Chauhan. "Recyclable Catalysts for Alkyne Functionalization." Molecules 26, no. 12 (2021): 3525. http://dx.doi.org/10.3390/molecules26123525.
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In this review, we present an assessment of recent advances in alkyne functionalization reactions, classified according to different classes of recyclable catalysts. In this work, we have incorporated and reviewed the activity and selectivity of recyclable catalytic systems such as polysiloxane-encapsulated novel metal nanoparticle-based catalysts, silica–copper-supported nanocatalysts, graphitic carbon-supported nanocatalysts, metal organic framework (MOF) catalysts, porous organic framework (POP) catalysts, bio-material-supported catalysts, and metal/solvent free recyclable catalysts. In addition, several alkyne functionalization reactions have been elucidated to demonstrate the success and efficiency of recyclable catalysts. In addition, this review also provides the fundamental knowledge required for utilization of green catalysts, which can combine the advantageous features of both homogeneous (catalyst modulation) and heterogeneous (catalyst recycling) catalysis.
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Kisszékelyi, Péter, Sándor Nagy, Zsuzsanna Fehér, Péter Huszthy, and József Kupai. "Membrane-Supported Recovery of Homogeneous Organocatalysts: A Review." Chemistry 2, no. 3 (2020): 742–58. http://dx.doi.org/10.3390/chemistry2030048.
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As catalysis plays a significant role in the development of economical and sustainable chemical processes, increased attention is paid to the recovery and reuse of high-value catalysts. Although homogeneous catalysts are usually more active and selective than the heterogeneous ones, both catalyst recycling and product separation pose a challenge for developing industrially feasible methods. In this respect, membrane-supported recovery of organocatalysts represents a particularly useful tool and a valid option for organocatalytic asymmetric synthesis. However, catalyst leaching/degradation and a subsequent decrease in selectivity/conversion are significant drawbacks. As the effectivity of the membrane separation depends mainly on the size of the catalyst in contrast to the other solutes, molecular weight enlargement of small organocatalysts is usually necessary. In the last few years, several synthetic methodologies have been developed to facilitate their recovery by nanofiltration. With the aim of extending the possibilities for the membrane-supported recovery of organocatalysts further, this contribution presents a review of the existing synthetic approaches for the molecular weight enlargement of organocatalysts.
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Regmi, Yagya N., Thomas Lau, Donato Decarolis, Andrew Beale, Magnus Ronning, and Laurie King. "Supported Iridium Catalysts for Water Electrolysers." ECS Meeting Abstracts MA2023-02, no. 42 (2023): 2091. http://dx.doi.org/10.1149/ma2023-02422091mtgabs.
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It is essential to reduce iridium in water electrolysers without compromising performance to lower the cost of green hydrogen. One strategy often used in catalysis to reduce precious metal catalyst usage is to deposit catalysts on high surface area supports. However, the catalyst supports need to be stable under the reaction conditions and also economically viable. Additionally, the catalyst-support moieties need to be sufficiently conductive. In this project, we explore platinum coated titanium dioxide as supports for iridium catalysts. Platinum is necessary to improve conductivity of the support motifs. Without this conductive platinum layer, extremely high (75 wt%) iridium loadings are needed to prepare commercially viable supported iridium catalysts.1, 2 In this work we synthesise and characterise a systematic series of catalysts whereby the Pt loading is varied in order to understand the loading effect on conductivity, and thus, electrocatalytic activities and durabilities. Previously, we have demonstrated the efficacy of a Pt conductive layer as an effective strategy for boosting the mass activity of Iridium in a half-cell configuration.4 However, translating the performance, more critically durability, in a device remained to be demonstrated. Here, we also begin by rapidly assessing the electrochemical performance of the library of prepared catalysts in a half-cell configuration (rotating disk electrodes, RDEs). Subsequently, catalysts that show promising activity and durability in half-cell are integrated into a PEM electrolyser. This approach is economic and efficient since integrating catalysts into membrane electrode assemblies and running electrolyser tests are resource and time intensive. However, there are challenges associated with replicating activity and durability from half-cell to device performance.3 Thus, we also explore methodologies and strategies to optimise our half-cell investigations to mimic full device conditions more closely. We have demonstrated that our strategy to engineer iridium catalysts has led to greater than 50% reduction in iridium content necessary in water electrolysers. And yet, our devices show performance and durability comparable to state-of-the-art technology. In this presentation we will discuss remaining challenges for hydrogen production using proton exchange membrane water electrolysers. We will also present materials characterisations and electrochemical performance of our catalysts in half-cell and full device configuration. Reference: K. Ayers, N. Danilovic, R. Ouimet, M. Carmo, B. Pivovar and M. Bornstein, Annu Rev Chem Biomol Eng, 2019, 10, 219-239. M. Bernt, A. Hartig‐Weiß, M. F. Tovini, H. A. El‐Sayed, C. Schramm, J. Schröter, C. Gebauer and H. A. Gasteiger, Chemie Ingenieur Technik, 2020, 92, 31-39. T. Lazaridis, B. M. Stühmeier, H. A. Gasteiger and H. A. El-Sayed, Nature Catalysis, 2022, 5, 363-373. Y. N. Regmi, E. Tzanetopoulos, G. Zeng, X. Peng, D. I. Kushner, T. A. Kistler, L. A. King and N. Danilovic, ACS Catalysis, 2020, 10, 13125-13135.
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Zhuang, Huimin, Bili Chen, Wenjin Cai, et al. "UiO-66-supported Fe catalyst: a vapour deposition preparation method and its superior catalytic performance for removal of organic pollutants in water." Royal Society Open Science 6, no. 4 (2019): 182047. http://dx.doi.org/10.1098/rsos.182047.
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A vapour deposition (VD) method was established for preparation of the UiO-66-supported Fe (Fe/UiO-66) catalyst, which provided the first case of the metal-organic framework (MOF)-supported Fe catalyst prepared by using the vapour-based method. The Fe loading was around 7.0–8.5 wt% under the present preparation conditions. The crystal structure of UiO-66 was not obviously influenced by the Fe loading, while the surface area significantly decreased, implicating most of the Fe components resided in the pores on UiO-66. The results for the methyl orange (MO) removal tests showed that MO in aqueous solution can be removed by UiO-66 by adsorption, and in contrast, it can be oxidized by H 2 O 2 with the catalysis of Fe/UiO-66. Further catalytic tests showed that Fe/UiO-66 was rather effective to catalyse the oxidation of benzene derivatives like aniline in water in terms of chemical oxygen demand (COD) removal efficiency. The catalytic test results for Fe/UiO-66 were compared to those of Fe/Al 2 O 3 with the same Fe loading and to the catalysts reported in the literature. This paper provides a general strategy for VD preparation of MOF-supported Fe catalyst on the one hand, and new catalysts for removing organic pollutants from water, on the other hand.
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Zong, Kening, Yanhui Hou, Xiaobei Zhao, Yali Sun, Binyuan Liu та Min Yang. "Slurry Homopolymerization of Ethylene Using Thermostable α-Diimine Nickel Catalysts Covalently Linked to Silica Supports via Substituents on Acenaphthequinone-Backbone". Polymers 14, № 17 (2022): 3684. http://dx.doi.org/10.3390/polym14173684.
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Four supported α-diimine nickel(II) catalysts covalently linked to silica via hydroxyl functionality on α-diimine acenaphthequinone-backbone were prepared and used in slurry polymerizations of ethylene to produce branched polyethylenes. The catalytic activities of these still reached 106 g/molNi·h at 70 °C. The life of the supported catalyst is prolonged, as can be seen from the kinetic profile. The molecular weight of the polyethylene obtained by the 955 silica gel supported catalyst was higher than that obtained by the 2408D silica gel supported catalyst. The melting points of polyethylene obtained by the supported catalysts S-C1-a/b are all above 110 °C. Compared with the homogeneous catalyst, the branching numbers of the polyethylenes obtained by the supported catalysts S-C1-a/b is significantly lower. The polyethylenes obtained by supported catalyst S-C1-a/b at 30–50 °C are free-flowing particles, which is obviously better than the rubber-like cluster polymer obtained from homogeneous catalyst.
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Shi, Chunjie, Xiaofeng Yu, Wei Wang, Haibing Wu, Ai Zhang, and Shengjin Liu. "The Activity and Cyclic Catalysis of Synthesized Iron-Supported Zr/Ti Solid Acid Catalysts in Methyl Benzoate Compounds." Catalysts 13, no. 6 (2023): 971. http://dx.doi.org/10.3390/catal13060971.
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The catalytic activity and cyclic catalysis of different methyl benzoates were studied by using a series of Lewis solid acid catalysts. The iron-supported zirconium/titanium solid acid catalysts were characterized using FTIR, SEM, XRD, and BET. The details of catalytic activity and cyclic catalysis verified that the catalyst catalyzed the reactions of 31 benzoic acids with different substituents and methanol. In addition, the mechanism was revealed according to the microstructure, acid strength, and specific surface area of the catalysts, and the yields of methyl benzoates by the GC-MS. Zr ions had significant effects on the catalytic activity of the catalyst. A certain proportion of Fe and Ti ions additionally enhanced the catalytic activity of the catalyst, with the catalyst-specific composition of Fe:Zr: Ti = 2:1: 1 showing optimal catalytic activity. A variety of substituents in the benzene ring, such as the electron-withdrawing group, the electron-donating group, large steric hindrance, and the position of the group on the benzene ring, had regular effects on the catalytic activity of the methyl benzoates. An increase in the catalyst activity occurred owing to the increases in the catalyst surface and the number of acid sites after the Fe ion was added. The catalytic activity remained unchanged after the facile recycling method was performed.
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Bergbreiter, David E., Andrew Kippenberger, and Zhenqi Zhong. "Catalysis with palladium colloids supported in poly(acrylic acid)-grafted polyethylene and polystyrene." Canadian Journal of Chemistry 84, no. 10 (2006): 1343–50. http://dx.doi.org/10.1139/v06-076.
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Grafts of poly(acrylic acid) on polyethylene powder (PE-g-PAA) or polystyrene (PS-g-PAA) can be used to support Pd(0) crystallites that function like a homogeneous Pd(0) catalyst in some reactions. These Pd–PE-g-PAA catalysts were active in allylic substitution reactions in the presence of added phosphine ligand. A catalyst analogous to the Pd–PE-g-PAA powder catalyst on polystyrene (Pd–PS-g-PAA) was similarly active for allylic substitution and could also be used in Heck reactions at 80–100 °C in N,N-dimethylacetamide (DMA). Analysis of the product solutions for Pd leachate and a correlation of the Pd leaching with product formation in the allylic substitution chemistry for both types of catalysts suggests that the active catalysts in these reactions are leached from the support. In the case of the allylic substitution reaction, external triphenylphosphine and substrate together are required for the chemistry and Pd leaching.Key words: catalysis, palladium, allylic substitution, grafted polystyrene, supported catalysts.
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Yao, Ming-Hui, David J. Smith, and Abhaya K. Datye. "Observation of supported catalyst particles by high-resolution SEM." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 782–83. http://dx.doi.org/10.1017/s042482010014974x.
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Supported metal particle catalysts have found wide application in the chemical industry and for environmental control. Many microscopy techniques have been employed to study these catalysts. Although scanning electron microscopy(SEM) is not commonly used, its ability to provide surface topological information as well as the ease of sample preparation and observation are positive attractions for catalysis research. Due to limited SEM resolution in the past, as well as severe charging of the insulating catalyst supports, very few studies of catalysts using SEM appear to have been reported. Recent development of in-lens specimen immersion systems and cold field emission sources of high brightness have made it possible to image specimen surfaces with secondary electrons at subnanometer resolution. Using a high resolution Hitachi S-5000 in-lens field emission SEM, we have studied Pt particles supported on TiO2 and CeO2. The purpose of this study was to evaluate relative merits and demerits of high resolution SEM for catalysis research, in particular with respect to TEM and STEM techniques.
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Yang, Ling Mei, Peng Mei Lv, Zhen Hong Yuan, et al. "Synthesis of Biodiesel by Different Carriers Supported KOH Catalyst." Advanced Materials Research 581-582 (October 2012): 197–201. http://dx.doi.org/10.4028/www.scientific.net/amr.581-582.197.
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Transesterification of soybean oil with methanol to methyl eaters was found proceed in the presence of KOH loaded on five different oxides (CaO, MgO, Al2O3, Bentonite, kaolin) as heterogeneous catalysts. The structure and performance of these catalysts were studied using the techniques of XRD, CO2-TPD, and SEM. It was found that the 15wt% KOH/CaO catalyst provided best activity. In the presence of this catalyst, the yield of fatty acid methyl esters was 97.1%. The reaction conditions were as follows: methanol to soybean oil molar ratio was 16:1, temperature of 65 °C, reaction time of 1 h, and a catalyst amount of 4 wt%. The catalysts of KOH loaded on CaO showed a new crystalline phase of K2O. However, the catalyst of 15-KOH/CaO has more basic sites than the catalyst of 15-KOH/MgO. Therefore, the catalyst of 15-KOH/CaO has been associated with higher transesterification activity.
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Mardwita, Mardwita, Eka Sri Yusmartini, and Nidya Wisudawati. "Effects of Cobalt and Chromium Loadings to The Catalytic Activities of Supported Metal Catalysts in Methane Oxidation." Bulletin of Chemical Reaction Engineering & Catalysis 15, no. 1 (2020): 213–20. http://dx.doi.org/10.9767/bcrec.15.1.6320.213-220.
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A series of alumina supported cobalt and chromium catalysts with different metal loadings were prepared by impregnation method. Six types of alumina supported cobalt and chromium catalysts contained 5 wt%, 10 wt%, and 15 wt% loadings were produced and tested in methane oxidation. The catalysts were characterized by using x-ray diffraction (XRD) and carbon monoxide chemisorption (CO chemisorption). The XRD results do not confirmed any features of cobalt and chromium metal. The metal sizes for both catalysts were larger in high loading as shown by CO chemisorption results. Methane conversion results showed that the conversion increases with increasing the metal loading, however supported chromium catalysts were higher in activities compared to supported cobalt catalysts. Thermal stability tests on 15 wt% Co/Al and 15 wt% Cr/Al catalyst showed that supported chromium catalyst is more stable and maintain the particle size due to its strong interaction with support, while supported cobalt catalyst decrease in methane conversion due to deactivation of the catalyst. Copyright © 2020 BCREC Group. All rights reserved
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Hauli, Latifah, Karna Wijaya, and Ria Armunanto. "Preparation of Cr Metal Supported on Sulfated Zirconia Catalyst." Materials Science Forum 948 (March 2019): 221–27. http://dx.doi.org/10.4028/www.scientific.net/msf.948.221.
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Catalyst of Chromium (Cr) metal supported on sulfated zirconia (SZ) was prepared by wet impregnation method. This study aim to determine the optimal concentration of Cr metal that impregnated on SZ catalyst. Preparation of catalyst was conducted at different concentrations of Cr metal (0.5%, 1%, 1.5% (w/w)), impregnated on SZ catalyst, then followed by the calcinationand reduction process. Catalysts were charaterized by FTIR, XRD, XRF, SAA, TEM, and acidity test. The results showed the Cr/SZ 1% had the highest acidity value of 8.22 mmol/g which confirmed from FTIR spectra. All the crystal phase of these catalysts were in monoclinic. The specific surface area increased with the increasing of Cr metal concentration on SZ catalyst and the isotherm adsorption-desorption of N2 gas observed all the catalysts as mesoporous material. The impregnation process formed particles agglomeration.
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Gupta, Raman, Monika Gupta, Satya Paul, and Rajive Gupta. "Silica-supported ZnCl2 — A highly active and reusable heterogeneous catalyst for the one-pot synthesis of dihydropyrimidinones–thiones." Canadian Journal of Chemistry 85, no. 3 (2007): 197–201. http://dx.doi.org/10.1139/v07-018.
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A novel silica-supported zinc chloride catalyst was prepared and investigated for the Biginelli reaction. The key features of the catalyst include rapid reaction with 100% conversion of aldehyde, good catalyst recyclability, and high stability under the reaction conditions (passes hot filtration test successfully). A low catalyst loading (12 mol% of ZnCl2) was required to achieve a quantitative reaction. Other catalysts such as SiO2–AlCl2, SiO2–AlCl2–ZnCl2 were also prepared and their activity was compared with SiO2–ZnCl2 for the Biginelli reaction.Key words: silica gel, zinc chloride, Biginelli compounds, heterogeneous catalysis, reusability.
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Alsalme, Ali, Aliyah A. Alsharif, Hamda Al-Enizi, et al. "Probing the Catalytic Efficiency of Supported Heteropoly Acids for Esterification: Effect of Weak Catalyst Support Interactions." Journal of Chemistry 2018 (July 24, 2018): 1–10. http://dx.doi.org/10.1155/2018/7037461.
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Supported heteropoly acids are an interesting class of solid acid catalysts which possess flexible structure and super acidic properties essentially required for the oil-based biodiesel production. In this study, a series of catalysts containing 25 wt.% of heteropolytungstate (HPW) supported on various clays or SiO2 were prepared, and their catalytic efficiency was evaluated for esterification of acetic acid with heptanol. The as-prepared catalysts were characterized by various techniques including FT-IR spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, and BET. The catalytic efficiency of both bulk and supported HPW catalysts for the esterification activity strongly depends on the type of support and amount of catalyst; the bulk HPW catalyst and the catalyst supported by kaolinite with 25 wt.% of HPW exhibited highest activity. In order to study the effect of temperature on conversion, all the catalysts were subjected to different reaction temperatures. It was revealed that esterification activity of both bulk and supported HPW catalysts strongly depends upon the temperature variations of the reaction. Besides, the effect of leaching of active sites on the catalysts performance for biodiesel production was also evaluated by inductively coupled plasma studies (ICP). The kaolinite-supported catalyst (25% HPW/kaolinite) demonstrated higher amount of leaching which is also confirmed by the significant decrease in its catalytic activity when it is used for the second time. However, the higher activity demonstrated by HPW/kaolinite maybe because of some homogeneous reaction indicating a weak catalyst support interaction (WCSI) resulting in the leaching of the catalyst during the test. Furthermore, the effects of other reaction variables such as catalyst loading and reaction time on the conversion of acetic acid were also studied.
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Khan, Wasim Ullah, Mohammad Rizwan Khan, Rosa Busquets, and Naushad Ahmad. "Contribution of Oxide Supports in Nickel-Based Catalytic Elimination of Greenhouse Gases and Generation of Syngas." Energies 14, no. 21 (2021): 7324. http://dx.doi.org/10.3390/en14217324.
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Carbon dioxide and/or dry methane reforming serves as an effective pathway to mitigate these greenhouse gases. This work evaluates different oxide supports including alumina, Y-zeolite and H-ZSM-5 zeolite for the catalysis of dry reforming methane with Nickel (Ni). The composite catalysts were prepared by impregnating the supports with Ni (5%) and followed by calcination. The zeolite supported catalysts exhibited more reducibility and basicity compared to the alumina supported catalysts, this was assessed with temperature programmed reduction using hydrogen and desorption using carbon dioxide. The catalytic activity, in terms of CH4 conversion, indicated that 5 wt% Ni supported on alumina exhibited higher CH4 conversion (80.5%) than when supported on Y-zeolite (71.8%) or H-ZSM-5 (78.5%). In contrast, the H-ZSM-5 catalyst led to higher CO2 conversion (87.3%) than Y-zeolite (68.4%) and alumina (83.9%) supported catalysts. The stability tests for 9 h time-on-stream showed that Ni supported with H-ZSM-5 had less deactivation (just 2%) due to carbon deposition. The characterization of spent catalysts using temperature programmed oxidation (O2-TPO), X-ray diffraction (XRD) and thermo-gravimetric analysis (TGA) revealed that carbon deposition was a main cause of deactivation and that it occurred in the lowest degree on the Ni H-ZSM-5 catalyst.
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Li, Chengyang, Hongyi Li, Libo Zhang, Yubo Ma, and Tianfu Wang. "Hydroformylation of Dicyclopentadiene to Monoformyltricyclodecenes over Supported Ultra-Low Content Rh Catalysts." Progress in Reaction Kinetics and Mechanism 43, no. 2 (2018): 166–72. http://dx.doi.org/10.3184/146867818x15233705894356.
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Five types of 0.006 wt% Rh catalyst supported on the surfaces of Al2O3, ZnO, TiO2(rutile), TiO2(anatase) and CeO2 were prepared by the incipient wetness method and used to catalyse the conversion of dicyclopentadiene (DCPD) to monoformyltricyclodecenes (MFTD). The 0.006 wt% Rh/ZnO catalyst showed the highest performance of the catalysts investigated and a 95.5% MFTD yield with 100% MFTD selectivity could be achieved. This suggested that there may be a key role for the carrier on the catalytic performance in the DCPD hydroformylation. Furthermore, the kinetic profiles for DCPD hydroformylation over the 0.006 wt% Rh/ZnO catalyst have been examined systematically to explore the effect of reaction temperature on the catalytic performance. These data collectively suggested that a specific reaction temperature might enhance DCPD hydroformylation, possibly owing to agglomeration of the active sites at higher reaction temperatures.
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du Plessis, Hester, Roy Forbes, Werner Barnard, Alta Ferreira, and Axel Steuwer. "In situ reduction study of cobalt model Fischer-Tropsch synthesis catalyst." Acta Crystallographica Section A Foundations and Advances 70, a1 (2014): C948. http://dx.doi.org/10.1107/s2053273314090512.
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Fischer-Tropsch (FT) synthesis is an important process to manufacture hydrocarbons and oxygenated hydrocarbons from mixtures of carbon monoxide and hydrogen (syngas). The catalysis process occurs on for example cobalt metal surfaces at elevated temperatures and pressures. A fundamental understanding of the reduction pathway of supported cobalt oxides, and the intermediate species present during the activation, can assist in developing improved industrial supported cobalt catalysts. Measurements were done during in-situ hydrogen activation of a model Co/alumina catalyst using in-situ synchrotron X-ray powder diffraction and pair-distribution function (PDF) analysis. Strong metal-support interactions between the Co and the support1 can make the catalyst more stable towards sintering. The supported cobalt oxide catalyst precursors have to undergo reductive pre-treatments before their use as FT catalysts. During activation the cobalt oxides evolve, resulting in the formation of metallic cobalt depending on temperature, pressure of activation gases, concentration, time of exposure etc. The effect of hydrogen activation treatments on model catalysts were reported previously [1,2], however analysis of the alumina support phases was excluded from the interpretation by subtraction and normalisation. The PDF refinement accounted for all cobalt present in the catalyst sample and after reduction mainly Co(fcc) with a little Co(hcp) was found to be present. This is a novel approach to in situ PDF analysis of catalysts containing a mixture of phases [3].
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Sviderskiy, S. A., O. S. Dement'eva, M. I. Ivantsov, A. A. Grabchak, M. V. Kulikova, and A. L. Maksimov. "Hydrogenation of CO2 over Biochar-Supported Catalysts." Нефтехимия 63, no. 2 (2023): 239–49. http://dx.doi.org/10.31857/s0028242123020089.
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The study investigates hydrogenation of CO2 over mono- and bimetallic catalysts supported on biochar. In this reaction, bimetallic iron–cobalt catalysts were shown to surpass monometallic iron and cobalt catalysts in terms of catalytic performance. The optimal combination of performance parameters was reached at an iron to cobalt ratio of 3 : 1. The composition and genesis of the active phase in the bimetallic Fe–Co catalyst were identified, and the CO2 hydrogenation mechanism was suggested for an iron-dominated bimetallic catalyst. Using biochar as a support was found to provide an active phase composition favorable for CO2 hydrogenation.
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Xu, Jun Qiang, Fang Guo, Jun Li, Xiu Zhi Ran, and Yan Tang. "Synthesis of the Cu/Flokite Catalysts and their Performances for Catalytic Wet Peroxide Oxidation of Phenol." Advanced Materials Research 560-561 (August 2012): 869–72. http://dx.doi.org/10.4028/www.scientific.net/amr.560-561.869.
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The supported Cu/Flokite catalysts were prepared by conventional incipient wetness impregnation. The catalysis oxidation degradation of phenol was carried out in heterogeneous catalyst and H2O2 process. The results indicated that the reaction system with catalyst and hydrogen peroxide was more benefit to degradation of phenol. When the phenol initial concentration was 100 mg/L, the phenol removal over the 2.5%Cu -2.5% Fe/Flokite catalyst could reach 96%. The peroxide catalytic oxidation process over the enhanced heterogeneous catalyst would be a novel technique for the treatment of phenol wastewater.
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Alharbi, Khadijah H., Walaa Alharbi, Sultan Alhayyani, L. Selva Roselin, and Rosilda Selvin. "Enhanced Oxidation of p-Toluidine Using Supported Zeolite Nanoparticles." Molecules 28, no. 15 (2023): 5737. http://dx.doi.org/10.3390/molecules28155737.
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Supported nanomaterials are becoming increasingly important in many industrial processes because of the need to improve both the efficiency and environmental acceptability of industrial processes. The unique properties of supported nanomaterials have attracted researchers to develop efficient catalytic materials in nanoscale. The extremely small size of the particles maximizes the surface area exposed to the reactant, allowing more reactions to occur. The environmental hazards resulting from the conventional manufacturing procedures for organic fine chemicals and intermediates by classical oxidation catalysis using mineral acids have forced chemical industries to seek less polluting processes. The present study aimed to oxidize p-toluidine by hydrogen peroxide in the presence of magnetite supported on nanocrystalline titanium silicalite-1 (M/NTS) zeolite at ambient temperature. The products detected are 4,4′-dimethylazobenzene as major product and 4,4′-dimethylazoxybenzene as minor product. Good selectivity, low cost, low wastage of materials and enhanced environmental friendliness of heterogeneous magnetite nanoparticle supported zeolite catalysts were observed. The effect of various reaction parameters such as mole ratio, catalyst weight and reusability of catalyst were studied. At the optimum reaction conditions, the oxidation activity of M/NTS catalyst was compared with M/NS catalyst, and it was found that titanium in the framework of M/NTS provided higher activity and selectivity.
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Zhang, Xiaolong, Shilei Jin, Yuhan Zhang, Liyuan Wang, Yang Liu, and Qian Duan. "One-Pot Facile Synthesis of Noble Metal Nanoparticles Supported on rGO with Enhanced Catalytic Performance for 4-Nitrophenol Reduction." Molecules 26, no. 23 (2021): 7261. http://dx.doi.org/10.3390/molecules26237261.
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In this study, reduced graphene oxide (rGO)-supported noble metal (gold, silver, and platinum) nanoparticle catalysts were prepared via the one-pot facile co-reduction technique. Various measurement techniques were used to investigate the structures and properties of the catalysts. The relative intensity ratios of ID/IG in rGO/Au, rGO/Ag, rGO/Pt, and GO were 1.106, 1.078, 1.047, and 0.863, respectively. The results showed the formation of rGO and that noble metal nanoparticles were decorated on rGO. Furthermore, the catalytic activities of the designed nanocomposites were investigated via 4-nitrophenol. The catalysts were used in 4-nitrophenol reduction. The catalytic performance of the catalysts was evaluated using the apparent rate constant k values. The k value of rGO/Au was 0.618 min−1, which was higher than those of rGO/Ag (0.55 min−1) and rGO/Pt (0.038 min−1). The result proved that the rGO/Au catalyst exhibited a higher catalytic performance than the rGO/Ag catalyst and the rGO/Pt catalyst. The results provide a facile method for the synthesis of rGO-supported nanomaterials in catalysis.
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Zhao, Xiaobei, Yanhui Hou, Linlin Ye та ін. "Synthesis of α-Diimine Complex Enabling Rapidly Covalent Attachment to Silica Supports and Application of Homo-/Heterogeneous Catalysts in Ethylene Polymerization". International Journal of Molecular Sciences 24, № 17 (2023): 13645. http://dx.doi.org/10.3390/ijms241713645.
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For covalent attachment-supported α-diimine catalysts, on the basis of ensuring the thermal stability and activity of the catalysts, the important problem is that the active group on the catalyst can quickly react with the support, anchoring it firmly on the support, shortening the loading time, reducing the negative impact of the support on the active centers, and further improving the polymer morphology, which makes them suitable for use in industrial polymerization temperatures. Herein, we synthesized a α-diimine nickel(II) catalyst bearing four hydroxyl substituents. The hydroxyl substituents enable the catalyst to be immobilized firmly on silica support by covalent linkage in 5–10 min. Compared with the toluene solvent system, the homogeneous catalysts show high activity and thermal stability in hexane solvent at the same conditions. Compared with homogeneous catalysts, heterogeneous catalysis leads to improvements in catalyst lifetime, polymer morphology control, catalytic activity, and the molecular weight of polyethylene (up to 679 kg/mol). The silica-supported catalysts resulted in higher melting temperatures as well as lower branching densities in polyethylenes. Even at 70 °C, the polyethylene prepared by S-CatA-2 still exhibits dispersed particle morphology, and there is no phenomenon of reactor fouling, which is suitable for industrial polymerization processes.
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Huang, Lin, Catherine Choong, Luwei Chen, et al. "Oxide-supported Rh catalysts for H2 generation from low-temperature ethanol steam reforming: effects of support, Rh precursor and Rh loading on catalytic performance." RSC Advances 5, no. 120 (2015): 99461–82. http://dx.doi.org/10.1039/c5ra14608a.
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Rh<sub>4</sub>(CO)<sub>12</sub>-derived Rh/CeO<sub>2</sub> is superior to the other oxide-supported Rh catalysts. Coking is the only cause of catalyst deactivation which affects the catalytic stability of Rh/CeO<sub>2</sub>. Both CeO<sub>2</sub>-supported Rh<sup>0</sup> and Rh<sup>+</sup> may participate in catalysis for ESR.
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Hsueh, C. L., Y. H. Huang, C. C. Wang, and C. Y. Chen. "Photooxidation of azo dye Reactive Black 5 using a novel supported iron oxide: heterogeneous and homogeneous approach." Water Science and Technology 53, no. 6 (2006): 195–201. http://dx.doi.org/10.2166/wst.2006.197.
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Photooxidation of azo dye Reactive Black 5 (RB5) by H2O2 was performed with a novel supported iron oxide in a batch reactor in the range of pH 2.5–6.0. The iron oxide was prepared through a fluidized-bed reactor (FBR) and much cheaper than the Nafion-based catalysts. Experimental results indicate that the iron oxide can significantly accelerate the degradation of RB5 under the irradiation of UVA light (λ=365 nm). An advantage of the catalyst is its long-term stability, which was confirmed through using the catalyst for multiple runs in the degradation of RB5. In addition, this study focused mainly on determining the proportions of homogeneous catalysis and heterogeneous catalysis in the batch reactor. Conclusively, although heterogeneous catalysis contributes primarily to the oxidation of RB5 during pH 4.5-6.0, the homogeneous catalysis is of increasing importance below pH 4.0 because of the Fe ions leaching from the catalyst to solution.
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Patil, Siddappa A., Shivaputra A. Patil, and Renukadevi Patil. "Magnetic Nanoparticles Supported Carbene and Amine Based Metal Complexes in Catalysis." Journal of Nano Research 42 (July 2016): 112–35. http://dx.doi.org/10.4028/www.scientific.net/jnanor.42.112.
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Catalysis is one of the hottest research topics in chemistry. In recent years, metal complexes attracted great interest as catalysts towards various types of organic reactions. However, these catalysts, in most cases, suffer from the deficits during their recovery, recycling and the difficulty in separation of catalysts from the products. Therefore, the design and synthesis of recoverable and recyclable catalyst is very important aspect in catalysis. The aim of this review article is to highlight the speedy growth in the synthesis and catalytic applications of magnetic nanoparticles (Fe3O4, MNPs) supported N-heterocyclic carbene (NHC) and amine based metal complexes in various organic reactions. Furthermore, these catalysts can be easily separated from the reaction media with the external magnet and reused various times without a substantial loss of catalytic activity.
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Ye, Ke, Ying Liu, Shubin Wu, and Junping Zhuang. "Efficient catalytic liquefaction of organosolv lignin over transition metal supported on HZSM-5." BioResources 17, no. 2 (2022): 2275–95. http://dx.doi.org/10.15376/biores.17.2.2275-2295.
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In this work, the catalytic liquefaction of eucalyptus organosolv lignin (EOL) over hydrogen type-zeolite socony mobile-five (HZSM-5) zeolite supported transition metals in an ethanol system was studied, and a cheap transition metal NiCr/HZSM-5 catalyst was prepared. Among them, nickel and chromium proved to have a good synergistic effect, which could remarkably enhance the acidity of the catalyst surface, and the catalytic effect was better than Ru-based precious metal catalysts and commercial Raney Ni catalysts. Meanwhile, the optimal reaction process of NiCr/HZSM-5 and Raney Ni catalyst for synergistic catalysis of EOL was explored. Under the optimal process conditions, the lignin liquefaction rate reached 95.9%, the monophenol yield was 8.64%, and the char content was only 2.08%. Furthermore, 1H-13C heteronuclear single quantum correlation nuclear magnetic resonance (1H-13C HSQC NMR) showed that the β-O-4, β-β, and β-5 linkages of lignin were effectively broken. Thus, a higher liquefaction rate of lignin was realized, which provided the possibility for further comprehensive utilization of lignin.
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Nishchakova, Alina D., Lyubov G. Bulusheva, and Dmitri A. Bulushev. "Supported Ni Single-Atom Catalysts: Synthesis, Structure, and Applications in Thermocatalytic Reactions." Catalysts 13, no. 5 (2023): 845. http://dx.doi.org/10.3390/catal13050845.
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Nickel is a well-known catalyst in hydrogenation and dehydrogenation reactions. It is currently used in industrial processes as a homogenous and heterogeneous catalyst. However, to reduce the cost and increase the efficiency of catalytic processes, the development of single-atom catalysts (SACs) seems promising. Some SACs have already shown increased activity and stability as compared to nanoparticle catalysts. From year to year, the number of reports devoted to nickel SACs is growing rapidly. Among them, there are very few articles devoted to thermal catalysis, but at the same time, this subject is important. Thus, this review discusses recent advances in the synthesis, structure, and application of nickel SACs, mainly in catalytic hydrogenation/dehydrogenation reactions and in the dry reforming of methane. The collected and analyzed data can be useful in the development of novel nickel SACs for various processes.
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Shareef, Muhammad Faizan, Muhammad Arslan, Naseem Iqbal, Nisar Ahmad, and Tayyaba Noor. "Development of Hydrotalcite Based Cobalt Catalyst by Hydrothermal and Co-precipitation Method for Fischer-Tropsch Synthesis." Bulletin of Chemical Reaction Engineering & Catalysis 12, no. 3 (2017): 357. http://dx.doi.org/10.9767/bcrec.12.3.762.357-362.
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This paper presents the effect of a synthesis method for cobalt catalyst supported on hydrotalcite material for Fischer-Tropsch synthesis. The hydrotalcite supported cobalt (HT-Co) catalysts were synthesized by co-precipitation and hydrothermal method. The prepared catalysts were characterized by using various techniques like BET (Brunauer–Emmett–Teller), SEM (Scanning Electron Microscopy), TGA (Thermal Gravimetric Analysis), XRD (X-ray diffraction spectroscopy), and FTIR (Fourier Transform Infrared Spectroscopy). Fixed bed micro reactor was used to test the catalytic activity of prepared catalysts. The catalytic testing results demonstrated the performance of hydrotalcite based cobalt catalyst in Fischer-Tropsch synthesis with high selectivity for liquid products. The effect of synthesis method on the activity and selectivity of catalyst was also discussed. Copyright © 2017 BCREC Group. All rights reservedReceived: 3rd November 2016; Revised: 26th February 2017; Accepted: 9th March 2017; Available online: 27th October 2017; Published regularly: December 2017How to Cite: Sharif, M.S., Arslan, M., Iqbal, N., Ahmad, N., Noor, T. (2017). Development of Hydrotalcite Based Cobalt Catalyst by Hydrothermal and Co-precipitation Method for Fischer-Tropsch Synthesis. Bulletin of Chemical Reaction Engineering & Catalysis, 12(3): 357-363 (doi:10.9767/bcrec.12.3.762.357-363)
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Shareef, Muhammad Faizan, Muhammad Arslan, Naseem Iqbal, Nisar Ahmad, and Tayyaba Noor. "Development of Hydrotalcite Based Cobalt Catalyst by Hydrothermal and Co-precipitation Method for Fischer-Tropsch Synthesis." Bulletin of Chemical Reaction Engineering & Catalysis 12, no. 3 (2017): 357. http://dx.doi.org/10.9767/bcrec.12.3.762.357-363.
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This paper presents the effect of a synthesis method for cobalt catalyst supported on hydrotalcite material for Fischer-Tropsch synthesis. The hydrotalcite supported cobalt (HT-Co) catalysts were synthesized by co-precipitation and hydrothermal method. The prepared catalysts were characterized by using various techniques like BET (Brunauer–Emmett–Teller), SEM (Scanning Electron Microscopy), TGA (Thermal Gravimetric Analysis), XRD (X-ray diffraction spectroscopy), and FTIR (Fourier Transform Infrared Spectroscopy). Fixed bed micro reactor was used to test the catalytic activity of prepared catalysts. The catalytic testing results demonstrated the performance of hydrotalcite based cobalt catalyst in Fischer-Tropsch synthesis with high selectivity for liquid products. The effect of synthesis method on the activity and selectivity of catalyst was also discussed. Copyright © 2017 BCREC Group. All rights reservedReceived: 3rd November 2016; Revised: 26th February 2017; Accepted: 9th March 2017; Available online: 27th October 2017; Published regularly: December 2017How to Cite: Sharif, M.S., Arslan, M., Iqbal, N., Ahmad, N., Noor, T. (2017). Development of Hydrotalcite Based Cobalt Catalyst by Hydrothermal and Co-precipitation Method for Fischer-Tropsch Synthesis. Bulletin of Chemical Reaction Engineering & Catalysis, 12(3): 357-363 (doi:10.9767/bcrec.12.3.762.357-363)
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Bai, Jirong, Yaoyao Deng, Yuebin Lian, Quanfa Zhou, Chunyong Zhang, and Yaqiong Su. "WCx-Supported RuNi Single Atoms for Electrocatalytic Oxygen Evolution." Molecules 28, no. 20 (2023): 7040. http://dx.doi.org/10.3390/molecules28207040.
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Single-atom catalysts anchored to oxide or carbonaceous substances are typically tightly coordinated by oxygen or heteroatoms, which certainly impact their electronic structure and coordination environment, thereby affecting their catalytic activity. In this study, we prepared a stable oxygen evolution reaction (OER) catalyst on tungsten carbide using a simple pyrolysis method. The unique structure of tungsten carbide allows the atomic RuNi catalytic site to weakly bond to the surface W and C atoms. XRD patterns and HRTEM images of the WCx-RuNi showed the characteristics of phase-pure WC and W2C, and the absence of nanoparticles. Combined with XPS, the atomic dispersion of Ru/Ni in the catalyst was confirmed. The catalyst exhibits excellent catalytic ability, with a low overpotential of 330 mV at 50 mA/cm2 in 1 m KOH solutions, and demonstrates high long-term stability. This high OER activity is ascribed to the synergistic action of metal Ru/Ni atoms with double monomers. The addition of Ni increases the state density of WCx-RuNi near the Fermi level, promoting the adsorption of oxygen-containing intermediates and enhancing electron exchange. The larger proximity of the d band center to the Fermi level suggests a strong interaction between the d electrons and the valence or conduction band, facilitating charge transfer. Our research offers a promising avenue for reasonable utilization of inexpensive and durable WCx carrier-supported metal single-atom catalysts for electrochemical catalysis.
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Xu, Jun Qiang, Fang Guo, Shu Shu Zou, and Xue Jun Quan. "Optimization of the Catalytic Wet Peroxide Oxidation of Phenol over the Fe/NH4Y Catalyst." Materials Science Forum 694 (July 2011): 640–44. http://dx.doi.org/10.4028/www.scientific.net/msf.694.640.
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The heterogeneous NH4Y zeolite-supported iron catalysts were prepared by incipient wetness impregnation. The catalysis oxidation degradation of phenol was carried over the heterogeneous catalyst in the peroxide catalytic oxidation process. Compared with the homogeneous Fenton process, the Fe/ NH4Y-acid catalyst can effectively degrade contaminants with high catalytic activity and easy catalyst separation from the solution. The phenol removal efficiency could reach 96% in the optimum experimental conditions. These process conditions were as follows: iron content is 5%, reaction time was 60 min, reaction temperature was 70 oC, the catalyst dosage was 1g/L, the H2O2 concentration was 1.65g/L.
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Liu, Xiaoyu, Wenqi Guo, Xueer Wang, et al. "TiCl4/MgCl2/MCM-41 Bi-Supported Ziegler–Natta Catalyst: Effects of Catalyst Composition on Ethylene/1-Hexene Copolymerization." Catalysts 11, no. 12 (2021): 1535. http://dx.doi.org/10.3390/catal11121535.
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TiCl4/MgCl2/MCM-41 type bi-supported Ziegler-Natta catalysts with different MgCl2/MCM-41 ratios were synthesized by adsorbing TiCl4 onto MgCl2 crystallites anchored in mesopores of MCM-41 (mesoporous silica with 3.4 nm pore size). Ethylene/1-hexene copolymerization with the catalysts was conducted at different 1-hexene concentrations and ethylene pressures. MgCl2/MCM-41 composite supports and the catalysts were characterized by X-ray diffraction (XRD), nitrogen adsorption analysis (BET), and elemental analysis. The copolymers were fractionated by extraction with boiling n-heptane, and comonomer contents of the fractions were determined. Under 4 bar ethylene pressure, the bi-supported catalysts showed higher activity and a stronger comonomer activation effect than the TiCl4/MgCl2 catalyst. In comparison with the TiCl4/MgCl2 catalyst, the bi-supported catalysts produced much less copolymer fraction of low molecular weight and high 1-hexene content, meaning that the active center distribution of the catalyst was significantly changed by introducing MCM-41 in the support. The copolymer produced by the bi-supported catalysts showed similar melting temperature to that produced by TiCl4/MgCl2 under the same polymerization conditions. The space confinement effect of the mesopores of MCM-41 on the size and structure of MgCl2 crystallites is proposed as the main reason for the special active center distribution of the bi-supported catalysts.
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Thongboon, Surached, Pacharaporn Rittiron, Danusorn Kiatsaengthong, Thanaphat Chukeaw, and Anusorn Seubsai. "Propylene Epoxidation to Propylene Oxide Over RuO2, CuO, TeO2, and TiO2 Supported on Modified Mesoporous Silicas." Journal of Nanoscience and Nanotechnology 20, no. 6 (2020): 3466–77. http://dx.doi.org/10.1166/jnn.2020.17408.
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Direct gas phase epoxidation of propylene to propylene oxide (PO) using O2 is a challenging problem in catalysis research. Silica-supported ruthenium-copper-based catalysts have been recently reported to be promising for propylene epoxidation. In this work, mesoporous silica supports modified with RuO2, CuO, and TeO2 with and without TiO2 were investigated for propylene epoxidation to PO. The prepared catalysts were divided into two groups. The first group consisted of mesoporous silica supports modified with RuO2, CuO, and TeO2, and the second group consisted of the same components as the first group but adding TiO2. The prepared supports and catalysts were characterized using BET surface area analysis and other advanced instrument techniques. It was found that the catalyst made with RuO2 and TeO2 impregnated onto porous silica modified with CuO and TiO2 (denoted as RuTe/CuTiSi) exhibited an excellent PO formation of 344 gPO h−1 kg−1cat, which was superior to that of the other prepared catalysts. Moreover, the addition of TiO2 into the catalyst greatly improved the PO formation rate and the arrangement of active components in the catalyst and strongly influenced catalytic performance.
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Chomboon, Tanakit, Weerit Kumsung, Metta Chareonpanich, Selim Senkan, and Anusorn Seubsai. "Chromium-Ruthenium Oxides Supported on Gamma-Alumina as an Alternative Catalyst for Partial Combustion of Methane." Catalysts 9, no. 4 (2019): 335. http://dx.doi.org/10.3390/catal9040335.
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Catalyst screening of γ-Al2O3-supported, single-metal and bimetallic catalysts revealed several bimetallic catalysts with activities for partial combustion of methane greater than a benchmark Pt/γ-Al2O3 catalyst. A cost analysis of those catalysts identified that the (2 wt%Cr + 3 wt% Ru)/γ-Al2O3 catalyst, denoted as 2Cr3Ru/Al2O3, was about 17.6 times cheaper than the benchmark catalyst and achieved a methane conversion of 10.50% or 1.6 times higher than the benchmark catalyst based on identical catalyst weights. In addition, various catalyst characterization techniques were performed to determine the physicochemical properties of the catalysts, revealing that the particle size of RuO2 became smaller and the binding energy of Ru 3d also shifted toward a lower energy. Moreover, the operating conditions (reactor temperature and O2/CH4 ratio), stability, and reusability of the 2Cr3Ru/Al2O3 catalyst were investigated. The stability test of the catalyst over 24 h was very good, without any signs of coke deposition. The reusability of the catalyst for five cycles (6 h for each cycle) was noticeably excellent.
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Jia, Wenzhi, Xia Cai, Yong Zhang, et al. "Catalytic Dehydrofluorination of Hydrofluoroalkanes to Fluorinated Olifein Over Ni/AlF3 Catalysts." MATEC Web of Conferences 238 (2018): 03004. http://dx.doi.org/10.1051/matecconf/201823803004.
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The hydrofluoric acid-resisting aluminum compounds (AlF3, AlPO4, AlN) supported with Ni catalyst were prepared by the wetness impregnation and tested for dehydrofluorination of hydrofluoroalkane to synthesize fluoroolefins. It is found that Ni/AlF3 catalyst has the best catalytic performance, CF3CFH2 conversion of 29.3% after the reaction at 430 °C for 30 h, CF2HCH3 conversion of 31.8% after the reaction at 250 °C for 30 h, respectively. Comparatively, dehydrofluorination temperature of CF3CFH2 is higher than CF2HCH3 over the aluminum compounds catalyst, and the activity of catalysts is related with Lewis acidity. For the aluminum compounds catalyst, addition of Ni had promoted the activity and stability of Lewis acidic catalysts, it is attributed to synergistic catalysis of Lewis acid sites and Ni.
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Wu, X., S. Bhatia, and T. S. King. "Supported catalyst characterization." Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films 10, no. 4 (1992): 2729–36. http://dx.doi.org/10.1116/1.577901.
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Zhao, Yue Qing, Qian Yi Jia, Ying Hua Liang, Hong Xia Guo, Feng Feng Li, and Xin Hua Liu. "CuO-CoO-MnO/SiO2 Nanocomposite Aerogel as Catalysts Carrier and Its Cocatalysis Mechanism in the Synthesis of Diphenyl Carbonate." Advanced Materials Research 284-286 (July 2011): 707–10. http://dx.doi.org/10.4028/www.scientific.net/amr.284-286.707.
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CuO-CoO-MnO/SiO2 nanocomposite aerogel as catalysts carrier was prepared via sol-gel process and CO2supercritical drying (SCD) technique. Catalyst supported by the nanocomposite aerogel was prepared via impregnation method. The catalyst was used for the synthesis of diphenyl carbonate (DPC), and the yield of DPC in mass is up to 26.31%. The catalysis system of PdCl2/Co(OAc)2-Cu(OAc)2-Mn(OAc)2/TBAB/H2BQ is favorable to the synthesis of DPC. PdCl2, acetates of transition metals and H2BQ were the key catalyst, inorganic cocatalyst and organic cocatalyst, respectively. TBAB was the surface active agent of Pd0and stabilizer of Pd2+in the catalysis system.
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Kim, Soohyun, Yunxia Yang, Renata Lippi, et al. "Low-Rank Coal Supported Ni Catalysts for CO2 Methanation." Energies 14, no. 8 (2021): 2040. http://dx.doi.org/10.3390/en14082040.
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As renewable energy source integration increases, P2G technology that can store surplus renewable power as methane is expected to expand. The development of a CO2 methanation catalyst, one of the core processes of the P2G concept, is being actively conducted. In this work, low-rank coal (LRC) was used as a catalyst support for CO2 methanation, as it can potentially enhance the diffusion and adsorption behavior by easily controlling the pore structure and composition. It can also improve the process efficiency owing to its simplicity (no pre-reduction step) and high thermal conductivity, compared to conventional metal oxide-supported catalysts. A screening of single metals (Ni, Co, Ru, Rh, and Pd) on LRC was performed, which showed that Ni was the most active. When Ni on the LRC catalyst was doped with a promoter (Ce and Mg), the CO2 conversion percentage increased by >10% compared to that of the single Ni catalyst. When the CO2 methanation activity was compared at 250–500 °C, the Ce-doped Ni/Eco and Mg-doped Ni/Eco catalysts showed similar or better activity than the commercial metal oxide-supported catalyst. In addition, the catalytic performance remained stable even after the test for an extended time (~200 h). The results of XRD, TEM, and TPR showed that highly efficient LRC-based CO2 methanation catalysts can be made when the metal dispersion and composition are modified.
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Frontera, Patrizia, Anastasia Macario, Angela Malara, et al. "CO2 and CO hydrogenation over Ni-supported materials." Functional Materials Letters 11, no. 05 (2018): 1850061. http://dx.doi.org/10.1142/s1793604718500613.
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This work reports on the fundamental properties of nanostructured catalysts active in the main carbon oxides’ conversion processes for sustainable energy supply: methanation and co-methanation of CO2. Transition metals (e.g. Ni, Pd, Pt, Co, Ru, Rh) are active species in both reactions. Ni has been the most studied because of its cheapness. Monometallic and bi-metallic Ni and Ni3Fe catalysts supported on Gadolinia-doped ceria (GDC) have been synthesized, characterized and tested in the temperature range 200–600[Formula: see text]C. In the methanation reaction, the monometallic catalyst showed higher performance with respect to the bi-metallic catalyst. At 400[Formula: see text]C, the CO2 conversion overcomes 90% with CH4 selectivity of 100%. In co-methanation, the highest CO2, CO and H2 conversion values over monometallic Ni/GDC catalyst were obtained at 300[Formula: see text]C; at higher temperatures, conversion decreases. The GDC support plays a pivotal role in both reactions, enhancing the basicity of the catalyst and improving the dissociation of carbon oxide species adsorbed on Ni sites.
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Qu, Jia, and Shaohong You. "Review on the Application and Preparation of Ozone Catalysts." E3S Web of Conferences 423 (2023): 02008. http://dx.doi.org/10.1051/e3sconf/202342302008.
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This paper reviews the recent advances in the application of ozone catalysts and their preparation. The main categories of ozone catalysts are introduced, and the properties of the more widely used metal oxide catalysts, supported catalysts, carbonaceous material catalysts and novel catalysts are summarized. The supported catalysts and carbonaceous material catalysts have better catalytic effect compared with metal oxide catalysts. The four most commonly used catalyst preparation methods are reviewed, and the prospects for catalyst development based on the current research status are presented.
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Grigoriev, Sergey, Vladimir Fateev, Artem Pushkarev, et al. "Reduced Graphene Oxide and Its Modifications as Catalyst Supports and Catalyst Layer Modifiers for PEMFC." Materials 11, no. 8 (2018): 1405. http://dx.doi.org/10.3390/ma11081405.
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Reduced graphene oxide (RGO) and RGO modified by ozone (RGO-O) and fluorine (RGO-F) were synthesized. Pt nanoparticles were deposited on these materials and also on Vulcan XC-72 using the polyol method. The structural and electrochemical properties of the obtained catalysts were investigated in a model glass three-electrode electrochemical cell and in a laboratory PEM fuel cell. Among the RGO-based catalysts, the highest electrochemically active surface area (EASA) was obtained for the oxidized RGO supported catalyst. The EASA of the fluorine-modified RGO-supported catalyst was half as big. In the PEM fuel cell the performance of RGO-based catalysts did not exceed the activity of Vulcan XC-72-based catalysts. However, the addition of an RGO-O-based catalyst to Vulcan XC-72-based catalyst (in contrast to the RGO-F-based catalyst) allowed us to increase the catalyst layer activity and PEM fuel cell performance. Possible reasons for such an effect are discussed.
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Li, Ruo Han, Song Zhou, Cai Ling Li, Zhi Yu Wang, and Yuan Qing Zhu. "A Study on SCR Catalyst Support." Advanced Materials Research 726-731 (August 2013): 17–20. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.17.
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NOx is one of the most serious atmosphere pollutants, and how to control and remove NOx is the hot research in the environmental field all over the world. SCR is considered as one of the most effective denitration methods at present. In SCR technology, catalyst is the core of the SCR system, and the performance of SCR catalyst mainly depends on the active component and catalyst support. Catalyst support can not only affect the choice of the active material and the catalyst promoter, but also affect the flue gas denitration efficiency. This paper mainly introduces four kinds of SCR catalyst supports: TiO2, Al2O3, activated carbon and activated carbon fiber and ZSM-5 zeolite. The performance of the four types of catalyst supports are compared, and SCR activity test of Mn-Ce supported and V2O5 supported on different catalyst supports are conducted respectively. Finally, for Mn-Ce supported and V2O5 supported catalysts, this paper puts forward that TiO2 is the most widely used and effective catalyst support.
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Saputra, Edy, Ahmad Fadli, Barata Aditya Prawiranegara, et al. "Hydrocarbon-Impacted Soils Supported Mn for Organic Pollutant Oxidation." Journal of Applied Materials and Technology 4, no. 2 (2024): 90–98. http://dx.doi.org/10.31258/jamt.4.2.90-98.
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Hydrocarbon-impeded soil (HIS) is solid waste from spills or leaks during industrial activities that negatively impact the environment. This study aims to utilize HIS as catalyst support on MnO2 to degrade RhB (RhB) solution using Peroxymonosulfate (PMS) and to determine the optimum conditions for the catalyst to degrade RhB. The catalyst was synthesized by reacting HIS, calcined with KMnO4 with various catalyst supports with high and low Total contain Petroleum Hydrocarbon (TPH). The process degradation of Rhodamine Solution was carried out with various catalysts, PMS, and RhB concentrations. The catalyst was characterized using X-ray diffraction (XRD), Nitrogen gas adsorption-desorption (BET), and Scanning Electron Microscope-Energy Disperse Spectroscope (SEM-EDX). In this study, the best catalyst performance was MnO2@H-TPH, which could activate PMS to degrade RhB with dye removal of 98% in about 180 min, at conditions 10 g/L RhB, 0.1 g/L catalyst, and 3 g/L PMS with the activation energy of 16.3 kJ/mol.
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Mistri, Rajib, and Bidyapati Kumar. "Supported Transition Metal Catalysts for Organic Fine Chemical Synthesis: A Review." Asian Journal of Chemistry 33, no. 3 (2021): 489–98. http://dx.doi.org/10.14233/ajchem.2021.23025.
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Transition metal catalysts play an important role for synthesis of industrially and laboratory important organic fine chemicals to control the selectivity, activity and stability. In this review, we focus on mainly transition metal based supported catalyst, mainly oxide supported catalyst for heterogeneous catalytic hydrogenation and oxidation of some synthetically important organic molecules. First we discuss the industrially important catalytic organic synthetic reactions. This is followed by the role of supported metal catalysts in the heterogeneous synthetic catalytic reactions with specific attention to hydrogenation and oxidation of organic molecules. The role of base metals and noble metals in monometallic and bimetallic catalysts are then discussed. Some synthetic routes for preparation of oxide supported metal catalysts are also discussed. Finally, a general discussion of the metal-support interaction (MSI) in oxide supported metal catalysts is made.
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Scholz, Guenter A., and S. Roy Morrison. "Methanation on exfoliated and supported MoS2." Canadian Journal of Chemistry 67, no. 5 (1989): 862–66. http://dx.doi.org/10.1139/v89-133.
Full textAbstract:
The methanation reaction on MoS2 exfoliated to a thickness of a few layers or less and adsorbed onto alumina is found to be very small. However, by calcining and resulfiding the exfoliated MoS2 catalysts, greatly improved performance is achieved that is at least equal to the commercial catalysts based on ammonium heptamolybdate. The creation of molybdenum oxysulflde surface species therefore appears to be a necessary step toward producing significant methanation rates with exfoliated and supported MoS2. The methanation products are almost exclusively CO2 and CH4, their mole ratios near unity, with otherwise only very much smaller amounts of longer chain hydrocarbons. The activation energy for methanation is generally observed to be near 100 kJ/mol, with the overall reaction being first order in the carbon monoxide concentration and third order in the hydrogen concentration. In contrast to the transition-metal catalysts, no water could be detected in the reaction products of the molybdenum based catalyst. Keywords: methanation reaction on MoS2, exfoliated and supported MoS2 as catalyst.