Journal articles: 'Copper catalysi'

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Dadashi-Silab, Sajjad, and Krzysztof Matyjaszewski. "Iron Catalysts in Atom Transfer Radical Polymerization." Molecules 25, no. 7 (April 3, 2020): 1648. http://dx.doi.org/10.3390/molecules25071648.

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Catalysts are essential for mediating a controlled polymerization in atom transfer radical polymerization (ATRP). Copper-based catalysts are widely explored in ATRP and are highly efficient, leading to well-controlled polymerization of a variety of functional monomers. In addition to copper, iron-based complexes offer new opportunities in ATRP catalysis to develop environmentally friendly, less toxic, inexpensive, and abundant catalytic systems. Despite the high efficiency of iron catalysts in controlling polymerization of various monomers including methacrylates and styrene, ATRP of acrylate-based monomers by iron catalysts still remains a challenge. In this paper, we review the fundamentals and recent advances of iron-catalyzed ATRP focusing on development of ligands, catalyst design, and techniques used for iron catalysis in ATRP.

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Trigoura, Leslie, Yalan Xing, and Bhanu P. S. Chauhan. "Recyclable Catalysts for Alkyne Functionalization." Molecules 26, no. 12 (June 9, 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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Querard, Pierre, Inna Perepichka, Eli Zysman-Colman, and Chao-Jun Li. "Copper-catalyzed asymmetric sp3 C–H arylation of tetrahydroisoquinoline mediated by a visible light photoredox catalyst." Beilstein Journal of Organic Chemistry 12 (December 6, 2016): 2636–43. http://dx.doi.org/10.3762/bjoc.12.260.

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This report describes a highly enantioselective oxidative sp3 C–H arylation of N-aryltetrahydroisoquinolines (THIQs) through a dual catalysis platform. The combination of the photoredox catalyst, [Ir(ppy)2(dtbbpy)]PF6, and chiral copper catalysts provide a mild and highly effective sp3 C–H asymmetric arylation of THIQs.

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Newman, R. A., J. A. Blazy, T. G. Fawcett, L. F. Whiting, and R. A. Stowe. "Use of the Dow-Developed DSC/XRD/MS in the Study of Several Model Copper-Based Catalyst Systems." Advances in X-ray Analysis 30 (1986): 493–502. http://dx.doi.org/10.1154/s0376030800021650.

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Due to the difficulty of analyzing materials at high temperatures and in reactive atmospheres, solid-state catalysts have often been developed with little knowledge of the true chemical behavior of the catalyst, except on a bulk scale. In the field of solid-state catalysis research, a great deal of time and effort is presently being spent to better characterize the chemical and physical properties which determine a particular catalyst‘s efficiency, lifetime, and selectivity. Recently, we have undertaken a study of model copper catalysts at The Dow Chemical Company in an effort to better understand the chemical and physical properties which determine the efficiency, regenerability, and lifetime of this type of solid state catalyst.

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Batool, Kiran, Rubia Shafique, Naseem Akhtar, Tahira Yaqoob, Muqaddas Jabeen, Arshad Mehmood, and Raheela Jabeen. "Synthesis and characterization of Zinc-Doped Copper Chromites by sol gel method." JOURNAL OF NANOSCOPE (JN) 2, no. 1 (June 30, 2021): 15–28. http://dx.doi.org/10.52700/jn.v2i1.23.

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Various preparation and application methods of copper chromites catalyst have recently been extensively discussed. According to all discussions, copper chromites is a versatile catalyst that not only catalyses many processes of national programmed and commercial importance, all of which are related to defense and space research, but also finds a lot of application in the most concerned worldwide, such as environmental pollution control. Copper chromites catalysts have many useful applications in the production of drugs, clean energy, and agro chemicals. Different synthesis methods are presented to prepare doped Zinc Copper chromites, demonstrating a clear understanding of the dependence of catalytic activity. This sample was created using a simple, eco-friendly sol gel method and characterized using various techniques such as EDS, SEM, UV, Raman spectroscopy, and Photoluminescence. Several parameters influence sample techniques. This sample was sintered in a furnace at 750°C for 4 hours. Zinc was successfully doped in copper chromites and emerged completely, according to EDS.

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Yun, Hafizah Abdul Halim, Ramli Mat, Tuan Amran Tuan Abdullah, Mahadhir Mohamed, and Anwar Johariand Asmadi Ali. "Activity of Copper and Nickel Loaded on HZSM-5Zeolite Based Catalyst for Steam Reforming of Glycerol to Hydrogen." Applied Mechanics and Materials 699 (November 2014): 504–9. http://dx.doi.org/10.4028/www.scientific.net/amm.699.504.

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The study focuses on hydrogen production via glycerol steam reforming over copper and nickel loaded on HZSM-5 zeolite based catalyst. The catalysts were prepared by using different loading amount of copper (0-10wt%) and nickel (0-10wt%) on HZSM-5 zeolite catalysts through wet impregnation method and was characterized by X-Ray Diffraction (XRD). The performances of catalysts were evaluated in terms of glycerol conversion and hydrogen production at 500°C using 6:1 of water to glycerol molar ratio (WGMR) in a tubular fixed bed reactor. All the catalysts had achieved more than 85% of glycerol conversion except that of 5%Cu loaded on HZSM-5 catalyst. The addition of nickel into 5% Cu/HZSM-5 catalyst had increased the hydrogen yield. Similar trend was observed when copper was added into Ni/HZSM-5 catalyst but using copper loaded on HZSM-5 alone was unable to produce hydrogen compared to using nickel catalyst alone. It showed that copper acted as a promoter for hydrogen production. It was established that a 5wt% of Cu with 10wt% of Ni loaded on HZSM-5 catalyst showed significant improvement in terms of hydrogen yield and gaseous product compositions at selected operating conditions.

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Santa Cruz-Navarro, Dalia, Miguel Torres-Rodríguez, Mirella Gutiérrez-Arzaluz, Violeta Mugica-Álvarez, and Sibele Berenice Pergher. "Comparative Study of Cu/ZSM-5 Catalysts Synthesized by Two Ion-Exchange Methods." Crystals 12, no. 4 (April 13, 2022): 545. http://dx.doi.org/10.3390/cryst12040545.

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As catalysis is one of the pillars of green chemistry, this work aimed at continuing the development of synthesized catalysts under controlled conditions that allow the attainment of materials with the best physicochemical properties for the process for which they were designed. Based on this, the synthesis, characterization, and comparison of copper-based catalysts supported on ammonium and acidic ZSM-5-type zeolite by two ion exchange methods, liquid phase and solid state, are presented. The catalysts obtained were characterized by SEM/EDS, FTIR, XRD, and TPR to study the effect of the synthesis method on the physicochemical properties of each catalyst. The SEM/EDS results showed a homogeneous distribution of copper in the zeolite and the TPR led to determining the temperature ranges for the reduction of Cu2+ → Cu+ → Cu0. Furthermore, the X-ray results showed no modification of the structure of the zeolite after ion exchange, heat treatment, and TPR analysis.

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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 (June 1, 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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Din, Israf Ud, Maizatul Shima Shaharun, Duvvuri Subbarao, and A. Naeem. "Synthesis, Characterization and Activity Pattern of Carbon Nanofibres Based Cu-ZrO₂ Catalyst in the Hydrogenation of Carbon Dioxide to Methanol." Advanced Materials Research 925 (April 2014): 349–53. http://dx.doi.org/10.4028/www.scientific.net/amr.925.349.

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Carbon nanofibers based Cu-ZrO2 catalysts (Cu-ZrO2/CNF) were synthesized by deposition precipitation method. Carbon nanofibers of herringbone type were used as a catalyst support. Before using as catalyst support, carbon nanofibers were oxidized to (CNF-O) with 10 % (v/v) nitric acid solution. A series of catalyst with various copper loadings of 10, 15 and 20 wt% were synthesized. X-ray diffraction (XRD) study revealed that degree of crystallization of catalyst increase with increasing the concentration of copper content in the catalyst. BET studies showed higher surface area for low loading of copper. Temperature-Programmed Reduction (TPR) analyses concluded good interaction of catalyst particles with higher loading of copper. The performance of Cu-ZrO2/CNF catalysts in hydrogenation of CO2 reaction was studied in slurry-typed reactor at 443 K, 30 bar and H2: CO2 ratio of 3:1. The highest yield of methanol was achieved using the 20 wt% copper loading.

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Nesterova, Oksana V., Armando J. L. Pombeiro, and Dmytro S. Nesterov. "Tetranuclear Copper Complexes with Bulky Aminoalcohol Ligands as Catalysts for Oxidative Phenoxazinone Synthase-like Coupling of Aminophenol: A Combined Experimental and Theoretical Study." Catalysts 12, no. 11 (November 10, 2022): 1408. http://dx.doi.org/10.3390/catal12111408.

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The new copper(II) complexes [Cu4(pa)4(Bae)4]·H2O (1) and [Cu4(eba)4(Buae)4]·H2O (2) (Hpa = propionic acid, HBae = 2-benzylaminoethanol, Heba = 2-ethylbutyric acid and HBuae = 2-butylaminoethanol) were synthesizsed by the interaction of a copper salt with a methanol solution of the respective ligands. The single-crystal X-ray diffraction analysis reveals that both compounds have a {Cu4(μ3-O)4} cubane-like core. Both compounds show pronounced phenoxazinone synthase-like activity towards the aerobic oxidation of o-aminophenol to phenoxazinone chromophore, with the maximum initial rates W0 up to 3.5 × 10−7 M s−1, and exhibit complex non-linear W0 vs. [catalyst]0 dependences. DFT//CCSD theoretical calculations (B3LYP/ma-def2-TZVP//DLPNO-CCSD(T)/ma-def2-TZVPP) were employed to investigate the most challenging steps of catalyst-free and copper-catalysed o-aminophenol oxidation (formation of o-aminophenoxyl radical). QTAIM analysis was used to study the key intermediates and weak interactions. Geometries and energies of intermediates and transition states were benchmarked against a series of popular DFT functionals. The results of the calculations demonstrate that a CuII–OO• copper-superoxo model catalyst decreases the calculated activation barrier from 28.7 to 19.9 kcal mol−1 for the catalyst-free and copper-catalysed abstraction of the H atom from the hydroxyl group of o-aminophenol, respectively. Finally, both complexes 1 and 2 were studied as catalysts in the amidation of cyclohexane with benzamide to give N-cyclohexyl benzamide and N-methyl benzamide employing di-tert-butyl peroxide (DTBP) as the oxidant, with a conversion of 16%, and in the oxidation of cyclohexane to cyclohexanol with aq. H2O2, with a conversion of 12%.

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11

Librando, Ivy L., Abdallah G. Mahmoud, Sónia A. C. Carabineiro, M. Fátima C. Guedes da Silva, Francisco J. Maldonado-Hódar, Carlos F. G. C. Geraldes, and Armando J. L. Pombeiro. "Heterogeneous Gold Nanoparticle-Based Catalysts for the Synthesis of Click-Derived Triazoles via the Azide-Alkyne Cycloaddition Reaction." Catalysts 12, no. 1 (December 31, 2021): 45. http://dx.doi.org/10.3390/catal12010045.

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A supported gold nanoparticle-catalyzed strategy has been utilized to promote a click chemistry reaction for the synthesis of 1,2,3-triazoles via the azide-alkyne cycloaddition (AAC) reaction. While the advent of effective non-copper catalysts (i.e., Ru, Ag, Ir) has demonstrated the catalysis of the AAC reaction, additional robust catalytic systems complementary to the copper catalyzed AAC remain in high demand. Herein, Au nanoparticles supported on Al2O3, Fe2O3, TiO2 and ZnO, along with gold reference catalysts (gold on carbon and gold on titania supplied by the World Gold Council) were used as catalysts for the AAC reaction. The supported Au nanoparticles with metal loadings of 0.7–1.6% (w/w relative to support) were able to selectively obtain 1,4-disubstituted-1,2,3-triazoles in moderate yields up to 79% after 15 min, under microwave irradiation at 150 °C using a 0.5–1.0 mol% catalyst loading through a one-pot three-component (terminal alkyne, organohalide and sodium azide) procedure according to the “click” rules. Among the supported Au catalysts, Au/TiO2 gave the best results.

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Yanagida, K., W. Kurniawan, C. Salim, and H. Hinode. "Decomposition of Nitrous Oxide over Cu/TiO2 Catalysts: The Effect of Cu Loading, TiO2 Structure, and Reaction Conditions." Indonesian Journal of Computing, Engineering and Design (IJoCED) 1, no. 2 (September 30, 2019): 99. http://dx.doi.org/10.35806/ijoced.v1i2.63.

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Decomposition of nitrous oxide (N2O) over titania (TiO2) supported copper (Cu) catalyst was investigated with the existence of oxygen and water vapor. The catalytic activity of TiO2 was promoted by copper loading. It was found that there are optimum levels of copper loading on TiO2, and these values are correlated to the specific surface area of TiO2 support being used. The relationship between the catalytic activity for decomposition of N2O and the crystal structure of TiO2 was also investigated. The result revealed that Cu/TiO2 catalysts with the rutile structure has a higher activity toward N2O decomposition than those with the anatase structure. In this research, Cu(5wt%)/TiO2 prepared from TiO2 JRC-TIO-4 (reference catalyst provided by Catalysis Society of Japan) which was mainly constituted of rutile showed the highest activity for N2O decomposition and it could decompose N2O completely at 650℃. The catalytic activity was inhibited by the existence of oxygen. However, there was no influence of water vapor to the catalytic activity of Cu/TiO2 for N2O decomposition.

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Maru, Minaxi S., Parth Patel, Noor-ul H. Khan, and Ram S. Shukla. "Copper Hydrotalcite (Cu-HT) as an Efficient Catalyst for the Hydrogenation of CO2 to Formic Acid." Current Catalysis 9, no. 1 (September 10, 2020): 59–71. http://dx.doi.org/10.2174/2211544709999200413110411.

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: Hydrogenation of CO2 to energy-rich products over heterogeneous metal catalysts has gained much attention due to their commercial applications. Specifically, the first-row transition metal catalysts are very rarely reported and discussed for the production of formic acid from the hydrogenation of CO2. Herein, hydrotalcite supported copper metal has shown activity and efficiency to produce formic acid from the hydrogenation of CO2, without adding any additional base or promoter and was effectively recycled 4 times after separating by simple filtration without compromising the formic acid yield. Hydrotalcite supported copper-based catalyst (Cu-HT) was synthesized through the coprecipitation method and used as a heterogeneous catalyst for the hydrogenation of CO2. The precise copper metal content determined by ICP in Cu-HT is 0.00944 mmol. The catalyst afforded maximum TOF, 124 h-1 under the employed reaction conditions: 100 mg catalyst, 60 °C, 60 bar total pressure of CO2/H2 (1:1, p/p) with 60 mL of mixed methanol:water (5:1, v/v) solvent. Cu-HT catalyst was synthesised and thoroughly characterized by FT-IR, PXRD, SEM, TEM, XPS and BET surface area. The first-order kinetic dependence with respect to the catalyst amount, partial pressures of CO2, and of H2 was observed and a plausible reaction mechanism is suggested. Background: CO2 hydrogenation to energy-rich products over heterogeneous metal catalysts has gained much attention due to their commercial applications. Specifically, the first-row transition metal catalysts are very rarely reported and discussed for the production of formic acid from the hydrogenation of CO2. Objective: he aim is to investigate the heterogeneous catalyst systems, using solid soft base hydrotalcite supported Cu metal-based catalyst for effective and selective hydrogenation of CO2 to formic acid. Methods: The Cu –HT catalyst was synthesized and characterized by FT-IR, PXRD, SEM, TEM, XPS and BET surface area in which the precise copper content was 0.00944 mmol. The Cu-HT catalysed hydrogenation of CO2 was carried out in the autoclave. Results: The Cu-HT catalyst afforded maximum TOF of 124 h-1 under the employed reaction conditions: 100 mg catalyst, 60 °C, 60 bar total pressure of CO2/H2 (1:1, p/p) with 60 mL of mixed methanol: water (5:1, v/v) solvent, without adding any additional base or promoter and was recycled 4 times by simple filtration without compromising the formic acid yield. Formation of formic acid was observed to depend on the amount of the catalyst, partial pressures of CO2 and H2, total pressure, temperature and time. Conclusion: Cu-HT based heterogeneous catalyst was found to be efficient for selective hydrogenation of CO2 to formic acid and was effectively recycled four times after elegantly separating by simple filtration.

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Lisovski, Oleg, Sergei Piskunov, Dmitry Bocharov, Yuri Zhukovskii, Janis Kleperis, Ainars Knoks, and Peteris Lesnicenoks. "CO2 and CH2 Adsorption on Copper-Decorated Graphene: Predictions from First Principle Calculations." Crystals 12, no. 2 (January 28, 2022): 194. http://dx.doi.org/10.3390/cryst12020194.

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Single-layer graphene decorated with monodisperse copper nanoparticles can support the size and mass-dependent catalysis of the selective electrochemical reduction of CO2 to ethylene (C2H4). In this study, various active adsorption sites of nanostructured Cu-decorated graphene have been calculated by using density functional theory to provide insight into its catalytic activity toward carbon dioxide electroreduction. Based on the results of our calculations, an enhanced adsorption of the CO2 molecule and CH2 counterpart placed atop of Cu-decorated graphene compared to adsorption at pristine Cu metal surfaces was predicted. This approach explains experimental observations for carbon-based catalysts that were found to be promising for the two-electron reduction reaction of CO2 to CO and, further, to ethylene. Active adsorption sites that lead to a better catalytic activity of Cu-decorated graphene, with respect to general copper catalysts, were identified. The atomic configuration of the most selective CO2 toward the reduction reaction nanostructured catalyst is suggested.

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Pei, Xiaojun, Haojun Shu, and Yisi Feng. "Preparation of Nitrogen-Doped Carbon-Based Bimetallic Copper-Cobalt Catalysis Based on Deep Learning and Its Monitoring Application in Furfural Hydrogenation." Scientific Programming 2022 (May 20, 2022): 1–8. http://dx.doi.org/10.1155/2022/7702776.

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In the field of catalysis, the support of the catalyst is often composed of hollow carbon materials. In order to monitor the preparation of nitrogen-doped carbon-based bimetallic copper-cobalt catalysis and its hydrogenation reaction in furfural, using m-aminophenol as the nitrogen source, formaldehyde as a carbon source, and P123 as a template agent, a nitrogen-doped bimetallic copper-cobalt mesoporous carbon catalyst Cu-Co@N-MPC-500 was synthesized by the hydrothermal method. The morphology, structure, and chemical composition of the catalyst were analyzed by means of TEM, XRD, BET, and XPS, respectively. The results show that the nitrogen-doped mesoporous carbon has a stable structure, uniform pore size distribution, and the nano-copper-cobalt particles are uniformly dispersed in the mesoporous carbon surface. Through furfural hydrogenation, the catalyst selectivity and cycle stability were discussed. Under the furfural conversion rate of 96.1%, the yield of cyclopentanone could reach 76.2%. After 5 cycles, the catalytic efficiency of the catalyst did not decrease significantly. It shows that Cu-Co@N-MPC-500 has excellent application prospects in the field of industrial production.

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Murahashi, Shun-Ichi, Naruyoshi Komiya, Yukiko Hayashi, and Tatsuyuki Kumano. "Copper complexes for catalytic, aerobic oxidation of hydrocarbons." Pure and Applied Chemistry 73, no. 2 (January 1, 2001): 311–14. http://dx.doi.org/10.1351/pac200173020311.

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Catalytic oxidation of hydrocarbons can be performed efficiently upon treatment with tert-butylhydroperoxide or peracetic acid in the presence of a low-valent ruthenium catalyst. Furthermore, aerobic oxidation of hydrocarbons can be performed in the presence of acetaldehyde using ruthenium, iron, and copper catalysts. Copper derived from copper chloride/crown ether or copper chloride/crown ether/alkaline metal salts have proved to be efficient catalysts. Further study revealed that specific copper complexes formed from copper salts and acetonitrile are convenient and highly useful catalysts for the aerobic oxidation of unactivated hydrocarbons.

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Schabes-Retchkiman, P. S., and L. Rendon. "Observation of catalytic Cu in methanol synthesis catalysts by atomic-resolution TEM." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 4 (August 1990): 284–85. http://dx.doi.org/10.1017/s0424820100174552.

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Much effort has been done for the characterization of catalysts in which CuO is found together with ZnO and ZnO/alumina, since these combinations constitute catalysts for the synthesis of methanol by the hydrogenation of carbon monoxide. Active catalysts are obtained after reduction in hydrogen at pressures between 50-100 atm and 225° to 275° C. The activity of the catalyst is largely due to the strong interaction between the CuO and ZnO phases. It is clear however that it is copper in various valence states, that is responsible for the catalytic activity, with the ZnO probably acting as both a structural and chemical promoter. However there is still controversy regarding the active sites for catalysis. Several hypotesis have been put forward: 1) The reaction occurs at isolated Cu(I) cations dissolved in the ZnO lattice. 2) The reaction occurs primarily on the metallic Cu component of the catalysts.

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Gousi, Mantha, Eleana Kordouli, Kyriakos Bourikas, Emmanouil Symianakis, Spyros Ladas, Christos Kordulis, and Alexis Lycourghiotis. "Green Diesel Production over Nickel-Alumina Nanostructured Catalysts Promoted by Copper." Energies 13, no. 14 (July 18, 2020): 3707. http://dx.doi.org/10.3390/en13143707.

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A series of nickel–alumina catalysts promoted by copper containing 1, 2, and 5 wt. % Cu and 59, 58, and 55 wt. % Ni, respectively, (symbols: 59Ni1CuAl, 58Ni2CuAl, 55Ni5CuAl) and a non-promoted catalyst containing 60 wt. % Ni (symbol: 60NiAl) were prepared following a one-step co-precipitation method. They were characterized using various techniques (N2 sorption isotherms, XRD, SEM-EDX, XPS, H2-TPR, NH3-TPD) and evaluated in the selective deoxygenation of sunflower oil using a semi-batch reactor (310 °C, 40 bar of hydrogen, 96 mL/min hydrogen flow rate, and 100 mL/1 g reactant to catalyst ratio). The severe control of the co-precipitation procedure and the direct reduction (without previous calcination) of precursor samples resulted in mesoporous nano-structured catalysts (most of the pores in the range 3–5 nm) exhibiting a high surface area (192–285 m2 g−1). The promoting action of copper is demonstrated for the first time for catalysts with a very small Cu/Ni weight ratio (0.02–0.09). The effect is more pronounced in the catalyst with the medium copper content (58Ni2CuAl) where a 17.2% increase of green diesel content in the liquid products has been achieved with respect to the non-promoted catalyst. The copper promoting action was attributed to the increase in the nickel dispersion as well as to the formation of a Ni-Cu alloy being very rich in nickel. A portion of the Ni-Cu alloy nanoparticles is covered by Ni0 and Cu0 nanoparticles in the 59Ni1CuAl and 55Ni5CuAl catalysts, respectively. The maximum promoting action observed in the 58Ni2CuAl catalyst was attributed to the finding that, in this catalyst, there is no considerable masking of the Ni-Cu alloy by Ni0 or Cu0. The relatively low performance of the 55Ni5CuAl catalyst with respect to the other promoted catalysts was attributed, in addition to the partial coverage of Ni-Cu alloy by Cu0, to the remarkably low weak/moderate acidity and relatively high strong acidity exhibited by this catalyst. The former favors selective deoxygenation whereas the latter favors coke formation. Copper addition does not affect the selective-deoxygenation reactions network, which proceeds predominantly via the dehydration-decarbonylation route over all the catalysts studied.

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Dey, Subhashish, Ganesh Chandra Dhal, Devendra Mohan, and Ram Prasad. "Effect of Preparation Conditions on the Catalytic Activity of CuMnOx Catalysts for CO Oxidation." Bulletin of Chemical Reaction Engineering & Catalysis 12, no. 3 (October 28, 2017): 437. http://dx.doi.org/10.9767/bcrec.12.3.900.437-451.

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The hopcalite (CuMnOx) catalyst is a well-known catalyst for oxidation of CO at ambient temperature. It has prepared by co-precipitation method and the preparation parameters were like Copper/Manganese (Cu:Mn) molar ratios, drying temperature, drying time, calcination temperature and calcination time has an influence on activity of the resultant catalyst. The activity of the catalyst was measured in flowing air calcinations (FAC) conditions. The reaction temperature was increased from ambient to a higher value at which complete oxidation of CO was achieved. The particle size, weight of catalyst and CO flow rate in the air were also influenced by the activity of the catalyst for CO oxidation. The characterizations of the catalysts were done by several techniques like XRD, FTIR, BET, SEM-EDX and XPS. These results were interpreted in terms of the structure of the active catalyst. The main aim of this paper was to identify the optimum preparation conditions of CuMnOx catalyst with respect to the performance of catalyst for CO oxidation. Copyright © 2017 BCREC Group. All rights reservedReceived: 9th January 2017; Revised: 24th May 2017; Accepted: 25th May 2017; Available online: 27th October 2017; Published regularly: December 2017How to Cite: Dey, S., Dhal, G.C., Mohan, D., Prasad, R. (2017). Effect of Preparation Conditions on the Catalytic Activity of CuMnOx Catalysts for CO Oxidation. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (3): 431-451 (doi:10.9767/bcrec.12.3.900.437-451)

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Chen, Wei, Lawrence F. Allard, Paul C. Dinh, Ming-Shin Tzou, and Kevin McIIwrath. "Microcharacterization of New Platinum Catalysts for Hydrosilylation Reactions." Microscopy and Microanalysis 7, S2 (August 2001): 1082–83. http://dx.doi.org/10.1017/s1431927600031482.

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Organofunctional silanes are the key intermediates for production of silicon polymeric chemicals. Traditionally, platinum catalysts on carbon support materials have been used for these hydrosilylation reactions. The efficiency of the current commercial Pt/C catalyst is not very satisfactory, so a catalyst of platinum on aluminum oxide support was developed to accelerate the reactions. The Pt/Al2O3catalyst greatly increases both reaction and conversion rates. However, the acidic nature of the supporting material is sometimes undesirable. Recently, a new class of platinum-copper bimetallic catalysts has been developed at Dow Corning, using co-deposition techniques with platinum chloride and copper chloride precursors. The bimetallic catalysts have also demonstrated significantly improved on hydrosilylation reaction efficiency and rates. The activity, selectivity, and stability of the catalysts are related to their structural properties, including catalyst particle size, size distribution, and particle composition. The knowledge of catalyst structures are, therefore, very important for understanding the performance of the catalysts and for optimizing production processes.

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Zhang, Yajing, Qian Wang, Zongsheng Yan, Donglai Ma, and Yuguang Zheng. "Visible-light-mediated copper photocatalysis for organic syntheses." Beilstein Journal of Organic Chemistry 17 (October 12, 2021): 2520–42. http://dx.doi.org/10.3762/bjoc.17.169.

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Photoredox catalysis has been applied to renewable energy and green chemistry for many years. Ruthenium and iridium, which can be used as photoredox catalysts, are expensive and scarce in nature. Thus, the further development of catalysts based on these transition metals is discouraged. Alternative photocatalysts based on copper complexes are widely investigated, because they are abundant and less expensive. This review discusses the scope and application of photoinduced copper-based catalysis along with recent progress in this field. The special features and mechanisms of copper photocatalysis and highlights of the applications of the copper complexes to photocatalysis are reported. Copper-photocatalyzed reactions, including alkene and alkyne functionalization, organic halide functionalization, and alkyl C–H functionalization that have been reported over the past 5 years, are included.

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Oisaki, Kounosuke, Motomu Kanai, Anne-Doriane Manick, and Hirotaka Tanaka. "Organophotoredox/Copper Hybrid Catalysis for Regioselective Allylic Aminodecarboxylation of β,γ-Unsaturated Carboxylic Acids." Synthesis 50, no. 15 (April 24, 2018): 2936–47. http://dx.doi.org/10.1055/s-0036-1591983.

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A new cooperative organophotoredox/copper catalysis allowing for the conversion of β,γ-unsaturated carboxylic acids into allylic hydrazides via radical regioselective allylic decarboxylative amination is reported. The coexistence of the copper catalyst is essential for the high yield and regioselectivity.

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Yang, Rui Qin, Xi Kun Gai, Chuang Xing, Jian Wei Mao, and Cheng Xue Lv. "Performance of Cu-Based Catalysts in Low-Temperature Methanol Synthesis." Advanced Materials Research 1004-1005 (August 2014): 1623–26. http://dx.doi.org/10.4028/www.scientific.net/amr.1004-1005.1623.

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The reactions of the methanol synthesis were conducted from the CO/CO2/H2 on the Cu-based catalysts using different solvent at 443 K and 3.0 MPa. The alcohol solvent had the activity in the low-temperature methanol synthesis reaction. The activity of the Cu-based catalyst with ZnO as carrier was higher than that of the catalyst with CeO2, Al2O3, or TiO2 as carrier separately in the reaction. The addition of the CeO2 to the Cu/ZnO catalysts improved the copper species dispersion, so that it was easier for the reduction of the Cu/CeO2-ZnO catalyst than that of the Cu/ZnO catalyst according to the TPR analysis. The variation trend of the BET surface area and the copper surface area was consistent with those of the activity for the Cu/ZnO and the Cu/CeO2-ZnO catalysts in the reaction. The activity of the Cu/CeO2-ZnO catalyst was higher than that of the Cu/ZnO catalyst in the reaction.

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Ma, Guoyan, Le Wang, Xiaorong Wang, Lu Li, and Hongfei Ma. "CO Oxidation over Alumina-Supported Copper Catalysts." Catalysts 12, no. 9 (September 10, 2022): 1030. http://dx.doi.org/10.3390/catal12091030.

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CO oxidation, one of the most important chemical reactions, has been commonly studied in both academia and the industry. It is one good probe reaction in the fields of surface science and heterogeneous catalysis, by which we can gain a better understanding and knowledge of the reaction mechanism. Herein, we studied the oxidation state of the Cu species to seek insight into the role of the copper species in the reaction activity. The catalysts were characterized by XRD, N2 adsorption-desorption, X-ray absorption spectroscopy, and temperature-programmed reduction. The obtained results suggested that adding of Fe into the Cu/Al2O3 catalyst can greatly shift the light-off curve of the CO conversion to a much lower temperature, which means the activity was significantly improved by the Fe promoter. From the transient and temperature-programmed reduction experiments, we conclude that oxygen vacancy plays an important role in influencing CO oxidation activity. Adding Fe into the Cu/Al2O3 catalyst can remove part of the oxygen from the Cu species and form more oxygen vacancy. These oxygen vacancy sites are the main active sites for CO oxidation reaction and follow a Mars-van Krevelen-type reaction mechanism.

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Saha, Debasree, and Chhanda Mukhopadhyay. "Metal Nanoparticles: An Efficient Tool for Heterocycles Synthesis and Their Functionalization via C-H Activation." Current Organocatalysis 6, no. 2 (June 24, 2019): 79–91. http://dx.doi.org/10.2174/2213337206666181226152743.

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Background: Metal nanoparticles have been extensively used in the synthesis of organic molecules during the last few decades especially due to their high catalytic activity. Organic reactions involving C-H functionalisations are very much in demand as they provide a direct method of derivatisation of organic molecules, thus making the process economical. In the recent years, metal nanoparticles catalysed C-H activation reactions have led to the design of useful molecules especially heterocyclic motifs which form the core structure of drugs and thus have high biological and industrial importance. Methods: In this review, we present a collection of reactions where metal nanoparticles are instrumental in the synthesis and functionalization of heterocycles via C-H activation. The review consists of three units namely, Nano-copper catalysed C-H activation reactions, nano-palladium catalysed CH activation reactions and other nano-metals catalysed C-H activation reactions. Results: The discussion reflects the scope of nano-metals as effective catalysts for the synthesis and functionalization of heterocycles as well as the efficiency of nano-metals towards catalysing economic and environmentally viable reaction protocols. Conclusion: The theme of this review is to correlate nanometal catalysis, heterocyclic synthesis and C-H activation, each of which in itself forms an integral part of modern day chemical research. Thus, the review will hopefully highlight the need for future development and research in this area and be instrumental in guiding researchers towards fulfilling that goal.

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Schmitz, Andrew D., Darrell P. Eyman, and Kenneth C. Moore. "Scanning Electron Microscopy of a supported molten salt CuC1-KCl/SiO2 catalyst." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 4 (August 1990): 286–87. http://dx.doi.org/10.1017/s0424820100174564.

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Carbon monoxide hydrogenation reactions catalyzed by heterogeneous catalysts are of significant industrial importance. Most methanol synthesis catalysts contain copper in synergism with ZnO and other metal oxide components. The chemical constitution and physical form of the copper phase in the working alcohol synthesis catalyst has been the subject of considerable concern. Recent NMR and x-ray, spectroscopic and microscopic investigation of alkali metal-promoted copper catalysts confirm earlier reports that the copper phase in methanol synthesis catalysts is a mixture of Cu(O) and Cu(I). Stabilization of a dispersion of Cu(I) is imperative for high activity.

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Kukushkin, R. G., P. M. Eletskiy, O. A. Bulavchenko, A. A. Saraev, and V. A. Yakovlev. "Studies of the Influence of Promoting the Ni/Al2O3 Catalyst with Copper on the Activity to Hydrotreatment of Esters." Kataliz v promyshlennosti 19, no. 1 (January 16, 2019): 40–49. http://dx.doi.org/10.18412/1816-0387-2019-1-40-49.

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The influence of the composition of the active component of copper-doped nickel catalysts on the activity and selectivity to hydrodeoxygenation (HDO) of model vegetable oils (esters) to eliminate oxygen and produce alkanes was studied. The Ni/Al2O3 andNi-Cu/Al2O3 catalysts were shown to be active to this process. They catalyzed HDO of a mixture of methyl ester of hexadecane acid and ethyl ester of decane acid to produce C6–C16 alkanes and oxygen-containing compounds, methane and ethane being detected in the gas phase. A decrease in the Ni/Cu ratio in the catalyst led to a decrease in the ester conversion and in the catalyst activity to hydrogenolysis of C–C bonds. Hence, the introduction of copper may favor preservation of the carbon skeleton of HDO-produced alkanes and a decrease in the methane yield. XRD studies revealed the formation of solid solutions Ni1–xCux upon addition of copper to the Ni/Al2O3 catalyst. From XPS data, an increase in the copper proportion in the Ni-Cu/Al2O3 catalyst resulted in a decrease in the Ni/Cu ration on the catalyst surface.

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Co, Thanh Thien. "Transfer hydrogenation of benzaldehyde over embedded copper nanoparticles." Science and Technology Development Journal 24, no. 1 (February 28, 2021): 1847–53. http://dx.doi.org/10.32508/stdj.v24i1.2507.

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Transfer hydrogenation is one of the reactions of high industrial application and copper catalyst is widely used in variety of hydrgenated substrates. Unfortunately, these hydrogenated processes were usually performed at high temperature and pressure as well as high concentration of catalyst. In this study, we have tried to reduce the dangerous condition by using copper nanoparticles as catalyst and the catalytic activity will be evaluated via the transfer hydrogenation of benzaldehyde. Besides, copper nanoparticles were successful prepared by the reduction between CuSO4.5H2O and NaBH4 in the presence of PVP. All catalysts were fully characterized.

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Todorova, Totka, Petya Petrova, and Yuri Kalvachev. "Catalytic Oxidation of CO and Benzene over Metal Nanoparticles Loaded on Hierarchical MFI Zeolite." Molecules 26, no. 19 (September 28, 2021): 5893. http://dx.doi.org/10.3390/molecules26195893.

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In order to obtain highly active catalytic materials for oxidation of carbon monoxide and volatile organic compounds (VOCs), monometallic platinum, copper, and palladium catalysts were prepared by using of two types of ZSM-5 zeolite as supports—parent ZSM-5 and the same one treated by HF and NH4F buffer solution. The catalyst samples, obtained by loading of platinum, palladium, and copper on ZSM-5 zeolite treated using HF and NH4F buffer solution, were more active in the reaction of CO and benzene oxidation compared with catalyst samples containing untreated zeolite. The presence of secondary mesoporosity played a positive role in increasing the catalytic activity due to improved reactant diffusion. The only exception was the copper catalysts in the reaction of CO oxidation, in which case the catalyst, based on untreated ZSM-5 zeolite, was more active. In this specific case, the key role is played by the oxidative state of copper species loaded on the ZSM-5 zeolites.

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Blieck, Rémi, Luca Perego, Ilaria Ciofini, Laurence Grimaud, Marc Taillefer, and Florian Monnier. "Copper-Catalysed Hydroamination of N-Allenylsulfonamides: The Key Role of Ancillary Coordinating Groups." Synthesis 51, no. 05 (February 13, 2019): 1225–34. http://dx.doi.org/10.1055/s-0037-1611673.

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A copper-catalysed hydroamination reaction of N-allenylsulfonamides with amines has been developed through a rational approach based on mechanistic studies. The reaction is promoted by a simple copper(I) catalyst and proceeds at room temperature with complete regioselectivity and excellent stereoselectivity towards linear (E)-N-(3-aminoprop-1-enyl)sulfonamides. Density Functional Theory (DFT) studies allow interpreting the key role of unsaturated substituents on nitrogen as ancillary coordinating moieties for the copper catalyst.

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Wang, Lin Tong. "Oxidation of Copper Zinc Oxide Catalysts by Carbon Monoxide." Advanced Materials Research 332-334 (September 2011): 564–67. http://dx.doi.org/10.4028/www.scientific.net/amr.332-334.564.

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Copper zinc oxide catalysts are effective for the ambient temperature carbon monoxide oxidation and display higher specific activity than the current commercial hopcalite catalyst. We investigate the copper zinc oxide catalyst prepared by co-precipitation under different atmospheres for the oxidation of carbon monoxide at low temperatures and these systems are now worthy of further investigation.

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García-Sancho, Cristina, Josefa María Mérida-Robles, Juan Antonio Cecilia-Buenestado, Ramón Moreno-Tost, and Pedro Jesús Maireles-Torres. "The Role of Copper in the Hydrogenation of Furfural and Levulinic Acid." International Journal of Molecular Sciences 24, no. 3 (January 26, 2023): 2443. http://dx.doi.org/10.3390/ijms24032443.

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Currently, there is a great interest in the development of sustainable and green technologies for production of biofuels and chemicals. In this sense, much attention is being paid to lignocellulosic biomass as feedstock, as alternative to fossil-based resources, inasmuch as its fractions can be transformed into value-added chemicals. Two important platform molecules derived from lignocellulosic sugars are furfural and levulinic acid, which can be transformed into a large spectrum of chemicals, by hydrogenation, oxidation, or condensation, with applications as solvents, agrochemicals, fragrances, pharmaceuticals, among others. However, in many cases, noble metal-based catalysts, scarce and expensive, are used. Therefore, an important effort is performed to search the most abundant, readily available, and cheap transition-metal-based catalysts. Among these, copper-based catalysts have been proposed, and the present review deals with the hydrogenation of furfural and levulinic acid, with Cu-based catalysts, into several relevant chemicals: furfuryl alcohol, 2-methylfuran, and cyclopentanone from FUR, and γ-valerolactone and 2-methyltetrahydrofuran from LA. Special emphasis has been placed on catalytic processes used (gas- and liquid-phase, catalytic transfer hydrogenation), under heterogeneous catalysis. Moreover, the effect of addition of other metal to Cu-based catalysts has been considered, as well as the issue related to catalyst stability in reusing studies.

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Mammadova, S. H., and A. A. Ahmadova. "DEPENDENCE OF Cr-Cu-O CATALYSTS ACTIVITY IN THE REACTION OF ETHANOL DEHYDROGENATION ON THEIR PHASE COMPOSITION." Chemical Problems 19, no. 1 (2021): 25–31. http://dx.doi.org/10.32737/2221-8688-2021-1-25-31.

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The work deals with the reaction of ethanol conversion over chromium copper binary oxide catalysts. It showed that acetaldehyde is the main product of the ethanol conversion reaction. As the temperature rises, the direction of the ethanol conversion reaction shifts toward dehydration of ethanol into ethylene. Studies revealed that the atomic ratio of chromium to copper in the composition of the catalyst also has a strong effect on the activity of chromium-copper oxide catalysts. It established that samples with high chromium content in the composition of the catalyst display the greatest activity in the reaction of acetic aldehyde formation. So, on the sample Cr-Cu = 6-4, the yield of acetaldehyde reaches 82.5% with a selectivity of 97.6%. X-ray studies found that Cr-Cu-O catalysts consist mainly of initial oxides and in some samples indicate the chemical compound. X-ray studies showed that as the copper content decreases, the degree of crystallinity increases in the studied catalytic system. Comparison of the activity of Cr-Cu-O catalysts with their crystallinity degree revealed that the rise in crystallinity degree of chromium-copper oxide catalysts leads to the increase of acetic aldehyde yield and its selectivity in the ethanol conversion reaction.

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Zhang, Lian Zi, and Hao Yuan Sun. "Development of Catalysts for Synthesizing Methanol from Syngas." Materials Science Forum 1053 (February 17, 2022): 165–69. http://dx.doi.org/10.4028/p-0eor9r.

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At present, methanol is one of the most basic organic chemical raw materials and energy storage media. With the development of chemical technology and energy storage technology, its application becomes more and more extensive, and the methanol market prospects are unlimited. Industrial-scale methanol is generally prepared by using synthesis gas containing hydrogen, carbon monoxide, and carbon dioxide as raw materials and reacting under a certain pressure, temperature, and catalyst. Therefore, the development of the methanol industry largely depends on the development of catalysts and the improvement of their performance. Metal catalysts are mainly used in the industry for reaction. This article reviews several metal catalysts used to synthesize methanol from syngas. Copper-based and iron-based catalysts are widely used, and the emerging rhodium and its ligand catalysts exhibit good catalytic performance in low-temperature catalysis. In the future, the scientific research team will focus on in-depth research on preparation methods, active centers, catalytic reaction kinetics, durability, metal ligands, raw material prices, etc., to lay a solid foundation for the industrial application of syngas to methanol in advance.

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35

Torregrosa-Rivero, Moreno-Marcos, Albaladejo-Fuentes, Sánchez-Adsuar, and Illán-Gómez. "BaFe1-xCuxO3 Perovskites as Active Phase for Diesel (DPF) and Gasoline Particle Filters (GPF)." Nanomaterials 9, no. 11 (October 31, 2019): 1551. http://dx.doi.org/10.3390/nano9111551.

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BaFe1-xCuxO3 perovskites (x = 0, 0.1, 0.3 and 0.4) have been synthetized, characterized and tested for soot oxidation in both Diesel and Gasoline Direct Injection (GDI) exhaust conditions. The catalysts have been characterized by BET, ICP-OES, SEM-EDX, XRD, XPS, H2-TPR and O2-TPD and the results indicate the incorporation of copper in the perovskite lattice which leads to: i) the deformation of the initial hexagonal perovskite structure for the catalyst with the lowest copper content (BFC1), ii) the modification to cubic from hexagonal structure for the high copper content catalysts (BFC3 and BFC4), iii) the creation of a minority segregated phase, BaOx-CuOx, in the highest copper content catalyst (BFC4), iv) the rise in the quantity of oxygen vacancies/defects for the catalysts BFC3 and BFC4, and v) the reduction in the amount of O2 released in the course of the O2-TPD tests as the copper content increases. The BaFe1-xCuxO3 perovskites catalyze both the NO2-assisted diesel soot oxidation (500 ppm NO, 5% O2) and, to a lesser extent, the soot oxidation under fuel cuts GDI operation conditions (1% O2). BFC0 is the most active catalysts as the activity seems to be mainly related with the amount of O2 evolved during an. O2-TPD, which decreases with copper content.

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Friedenberg, Daniel S., David C. Manns, Demetra M. Perry, and Anna Katharine Mansfield. "Removal of Copper from White Wine: Imidazole-Based Polymers Are Efficient at Copper Adsorption." Catalyst: Discovery into Practice 2, no. 1 (January 25, 2018): 1–6. http://dx.doi.org/10.5344/catalyst.2018.17007.

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37

Goyal, Sonam, Maizatul Shaharun, Chong Kait, Bawadi Abdullah, and Mariam Ameen. "Photoreduction of Carbon Dioxide to Methanol over Copper Based Zeolitic Imidazolate Framework-8: A New Generation Photocatalyst." Catalysts 8, no. 12 (November 25, 2018): 581. http://dx.doi.org/10.3390/catal8120581.

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The efficient reduction of CO2 into valuable products such as methanol, over metal-organic frameworks (MOFs) based catalyst, has received much attention. The photocatalytic reduction is considered the most economical method due to the utilization of solar energy. In this study, Copper (II)/Zeolitic Imidazolate Framework-8 (Cu/ZIF-8) catalysts were synthesized via a hydrothermal method for photocatalytic reduction of CO2 to methanol. The synthesized catalysts were characterized by X-ray Photoelectron Spectroscopy (XPS), Field Emission Scanning Electron Microscopy (FESEM) coupled with Energy Dispersive X-ray (EDX), Ultraviolet-visible (UV-vis) spectroscopy, and X-Ray Diffraction (XRD). The host ZIF-8, treated with 2 mmol copper prepared in 2M ammonium hydroxide solution showed the highest photocatalytic activity. The crystal structures of ZIF-8 and 2Cu/ZIF-8N2 catalysts were observed as cubic and orthorhombic, respectively and the XPS analysis confirmed the deposition of Cu (II) ions over ZIF-8 surface among all the prepared catalysts. The orthorhombic structure, nano-sized crystals, morphology and Cu loading of the 2Cu/ZIF-8N2 catalyst were the core factors to influence the photocatalytic activity. The yield of Methanol was found to be 35.82 µmol/L·g after 6 h of irradiations on 2Cu/ZIF-8N2 catalyst in the wavelength range between 530–580 nm. The copper-based ZIF-8 catalyst has proven as an alternative approach for the economical photocatalytic reduction of CO2 to CH3OH.

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Zhi, Ke Duan, Quan Sheng Liu, Run Xia He, Fang Wu, Ya Gang Zhang, and Li Yang. "Copper-Based Mixed Oxides Catalyst of Water-Gas Shift Reaction for Fuel Cells: The Role of Alkali Charge." Applied Mechanics and Materials 268-270 (December 2012): 538–41. http://dx.doi.org/10.4028/www.scientific.net/amm.268-270.538.

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The effects of alkali charge on the activity and stability of copper-based mixed oxides catalyst for the water-gas shift reaction (WGSR) were investigated. Activity tests showed that the copper-based mixed oxides catalyst while the 2[NaOH]/[Cu2++Mn2+] is above 1.2 displayed higher activity and better stability than that of others catalysts. The BET , XRD and TPR results revealed that the Cu-Mn catalyst while the 2[NaOH]/[Cu2++Mn2+] is above 1.2 led to higher surface area, a more stable catalyst structure and suitable reduction performance, in turn leading to better catalytic behavior for the Cu-Mn catalyst.

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39

Frikha, Kawthar, Lionel Limousy, Jamel Bouaziz, Kamel Chaari, Ludovic Josien, Habiba Nouali, Laure Michelin, Loic Vidal, Samar Hajjar-Garreau, and Simona Bennici. "Binary Oxides Prepared by Microwave-Assisted Solution Combustion: Synthesis, Characterization and Catalytic Activity." Materials 12, no. 6 (March 19, 2019): 910. http://dx.doi.org/10.3390/ma12060910.

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Three different alumina-based Ni, Cu, Co oxide catalysts with metal loading of 10 wt %, and labeled 10Ni–Al, 10Co–Al and 10Cu–Al, were prepared by microwave-assisted solution combustion. Their morphological, structural and surface properties were deeply investigated by complementary physico-chemical techniques. Finally, the three materials were tested in CO oxidation used as test reaction for comparing their catalytic performance. The 10Cu–Al catalyst was constituted of copper oxide phase, while the 10Ni–Al and 10Co–Al catalysts showed the presence of “spinels” phases on the surface. The well-crystallized copper oxide phase in the 10Cu–Al catalyst, obtained by microwave synthesis, allowed for obtaining very high catalytic activity. With a CO conversion of 100% at 225 °C, the copper containing catalyst showed a much higher activity than that usually measured for catalytic materials of similar composition, thus representing a promising alternative for oxidation processes.

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Menshikov, Vladislav S., Ivan N. Novomlinsky, Sergey V. Belenov, Anastasya A. Alekseenko, Olga I. Safronenko, and Vladimir E. Guterman. "Methanol, Ethanol, and Formic Acid Oxidation on New Platinum-Containing Catalysts." Catalysts 11, no. 2 (January 23, 2021): 158. http://dx.doi.org/10.3390/catal11020158.

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Electrooxidation of methanol, ethanol, and formic acid was studied on three platinum-containing electrocatalysts: PtCu/C, Pt/(SnO2/C), and Pt/C, Pt content being about 20 wt%. In all reactions, the integral specific activity of the catalysts, estimated from the results of cyclic voltammetry, grows in the Pt/C < Pt/(SnO2/C) < PtCu/C row. The influence of the reagent nature subjected to electrooxidation is manifested both in the difference of the absolute rate values of the corresponding reactions, decreasing in the order CH3OH > HCOOH > C2H5OH, and in the different ratio of these rates on different catalysts and at different potentials. Pt/(SnO2/C) catalyst containing SnO2 nanoparticles is the most active among the studied catalysts in methanol and formic acid electrooxidation reactions under potentiostatic conditions at the E = 0.60 V. Moreover, in formic acid electrooxidation reaction it is significantly superior to even the PtRu/C commercial catalyst. The reasons for the positive influence of Cu atoms and SnO2 nanoparticles on the catalytic activity of platinum are presumably associated with different effects: Interaction of the d-orbitals of copper and platinum atoms in bimetallic nanoparticles and implementation of the bifunctional catalysis mechanism on the adjacent platinum and tin dioxide nanoparticles.

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Nguyen, Oanh T. K., Ha Trong Pha, Huynh Dang Khoa, Duy Chinh Nguyen, and Nguyen Thi Hong Tam. "Copper Ferrite Superparamagnetic Nanoparticle-Catalyzed Cross-coupling Reaction to Form Diindolylmethane (DIM): Effect of Experimental Parameters." Bulletin of Chemical Reaction Engineering & Catalysis 15, no. 3 (July 31, 2020): 631–40. http://dx.doi.org/10.9767/bcrec.15.3.8228.631-640.

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Superparamagnetic copper ferrite (CuFe2O4) nanoparticles were utilized as a heterogenous catalyst for the cross-coupling reaction of indole to form 3,3’-diindolylmethane (DIM) as the desirable product. High reaction yield, at around 82%, was achieved under optimal conditions. The CuFe2O4 material could be easily separated from the reaction mixture by an external magnetic field and could be reutilized several times without a significant decrease in catalytic activity. We also showed that no sites of catalyst material leached into reaction solution was detected. To our best knowledge, the above cross-coupling reaction was not previously conducted under catalysis of superparamagnetic nanoparticles. Copyright © 2020 BCREC Group. All rights reserved

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42

Kurta, Sergiy, Ihor Mykytyn, Victoria Ribun, and Olga Khatsevich. "Features of the structure active centers of industrial catalysts for the oxidative chlorination of ethylene." International Journal of Engineering & Technology 7, no. 2.23 (April 20, 2018): 307. http://dx.doi.org/10.14419/ijet.v7i2.23.12751.

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The active phase of CuCl2, HСuСl2, H2СuСl4 and two grades of industrial ethylene oxidation chlorination catalysts (EOC) such as deposited catalyst X1 (Harshow), with copper chlorides supported on an alumina surface, and a permeated MEDC-B catalyst immobilized in the internal pores of the firm of the company Sud-Chemie. Catalyst were analyzed by the method of thermoemission electronic raster (VEGA3NTSCAN) microscopy and X-ray fluorescence energy dispersion spectroscopy (EDX-7000). It is shown that the active catalyst centers of CuCl2 have different crystalline structure from the amorphous active phase of H2CuCl2, H2CuCl4 on the surface of the catalysts. On the surface of X1 Harshow copper chlorides are uniformly distributed throughout the volume of the carrier catalyst γ-Al2O3 in the form of amorphous portions [CuCl4]-2, [CuCl2]-1. At the same time, on the surface of the catalyst MEDC-B, the active centers have a separate cluster immobilized crystalline structure of the active phase, which differs from the composition of the carrier γ-Al2O3.

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To Anh, Tuong, Trang Nguyen Thi Thuy, Anh Nguyen Thai, and Nam Phan Thanh Son. "Cu2(BDC)2DABCO as an efficient heterogeneous catalyst for the oxidative C-N coupling reaction between amides and unactivated alkanes." Vietnam Journal of Catalysis and Adsorption 9, no. 1 (April 30, 2020): 67–72. http://dx.doi.org/10.51316/jca.2020.011.

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A copper-organic framework Cu2(BDC)2DABCO was synthesized, and used as a recyclable heterogeneous catalyst for C-N coupling reaction between benzamide and cyclohexane. 94% yield of N-cyclohexylbenzamide was achieved under the optimized condition. The copper-organic framework catalyst was truly heterogeneous and could be used at least 4 cycles without degradation of catalytic performance. To the best of our knowledge, the amidation of unactivated alkanes by benzamides via direct oxidative C-N coupling was previously performed under heterogeneous catalysis conditions but very rare.

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Rudd, Jennifer A., Sandra Hernandez-Aldave, Ewa Kazimierska, Louise B. Hamdy, Odin J. E. Bain, Andrew R. Barron, and Enrico Andreoli. "Investigation into the Re-Arrangement of Copper Foams Pre- and Post-CO2 Electrocatalysis." Chemistry 3, no. 3 (June 28, 2021): 687–703. http://dx.doi.org/10.3390/chemistry3030048.

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The utilization of carbon dioxide is a major incentive for the growing field of carbon capture. Carbon dioxide could be an abundant building block to generate higher-value chemical products. Herein, we fabricated a porous copper electrode capable of catalyzing the reduction of carbon dioxide into higher-value products, such as ethylene, ethanol and propanol. We investigated the formation of the foams under different conditions, not only analyzing their morphological and crystal structure, but also documenting their performance as a catalyst. In particular, we studied the response of the foams to CO2 electrolysis, including the effect of urea as a potential additive to enhance CO2 catalysis. Before electrolysis, the pristine and urea-modified foam copper electrodes consisted of a mixture of cuboctahedra and dendrites. After 35 min of electrolysis, the cuboctahedra and dendrites underwent structural rearrangement affecting catalysis performance. We found that alterations in the morphology, crystallinity and surface composition of the catalyst were conducive to the deactivation of the copper foams.

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Yakoumis, Iakovos, Εkaterini Polyzou, and Anastasia Maria Moschovi. "PROMETHEUS: A Copper-Based Polymetallic Catalyst for Automotive Applications. Part II: Catalytic Efficiency an Endurance as Compared with Original Catalysts." Materials 14, no. 9 (April 26, 2021): 2226. http://dx.doi.org/10.3390/ma14092226.

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PROMETHEUS catalyst, a copper-based polymetallic nano-catalyst has been proven to be suitable for automotive emission control applications. This novel catalyst consists of copper, palladium and rhodium nanoparticles as active phases, impregnated on an inorganic oxide substrate, CeO2/ZrO2 (75%, 25%). The aim of PROMETHEUS catalyst’s development is the substitution of a significant amount (85%) of Platinum Group Metals (PGMs) with copper nanoparticles while, at the same time, presenting high catalytic efficiency with respect to the commercial catalysts. In this work, an extensive investigation of the catalytic activity of full scale PROMETHEUS fresh and aged catalyst deposited on ceramic cordierites is presented and discussed. The catalytic activity was tested on an Synthetic Gas Bench (SGB) towards the oxidation of CO and CH4 and the reduction of NO. The loading of the washcoat was 2 wt% (metal content) on Cu, Pd, Rh with the corresponding metal ratio at 21:7:1. The concentration of the full-scale monolithic catalysts to be 0.032% total PGM loading for meeting Euro III standard and 0.089% for meeting Euro IV to Euro VIb standards. The catalytic activity of all catalysts was tested both in rich-burn (λ = 0.99) and lean-burn conditions (λ = 1.03).

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Popov, Yu V., V. M. Mokhov, D. N. Nebykov, P. M. Shirkhanyan, T. A. Gendler, and V. V. Shemet. "THE INVESTIGATION OF FURAN DERIVATIVES HYDROGENATION PROCESS IN PRESENCE OF COPPER AND COBALT CATALYSTS, SUPPORTED ON MGO." IZVESTIA VOLGOGRAD STATE TECHNICAL UNIVERSITY, no. 5(240) (May 19, 2020): 7–10. http://dx.doi.org/10.35211/1990-5297-2020-5-240-7-10.

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The hydrogenation of furfural during catalysis by copper nanoparticles deposited on MgO in a gas phase displacement reactor or in a gas-liquid-solid catalyst system proceeds at atmospheric pressure of hydrogen.

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Cui, Yan, Xuemei Ran, Zequan Zeng, Zhanggen Huang, and Jieyang Yang. "In Situ Preparation of Copper-Loaded Carbon-Based Catalyst with Chelate Resin and Its Application on Persulfate Activation for X-3B Degradation." Catalysts 10, no. 11 (November 17, 2020): 1333. http://dx.doi.org/10.3390/catal10111333.

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Under the guidance of the idea of “treating waste with waste”, copper-loaded carbon-based catalysts were prepared in situ using waste chelating resin with adsorbed copper. The effect of the catalyst activation temperature on dye brilliant red (X-3B) degradation was investigated and the characterization of the catalysts was analyzed. The results show that a catalyst activated at 800 °C (Cu-AC-800) has the largest specific surface area and abundant pore structure and the highest proportion of Cu under low valence states, which leads to the best performance in adsorbing and degrading X-3B. The influences of operation conditions and inorganic salt anions on persulfate (PS) activation were also investigated. Moreover, the degradation mechanism was preliminarily explored by quenching reactions. The main active free radicals in the system were determined as sulfate radicals (•SO4−). Given its use in solid waste recycling, copper-loaded carbon-based catalyst may provide some new insights for the remediation of wastewater.

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48

Zhao, Ruonan, Chenyu Yan, Yuanyuan Jiang, and Mingzhong Cai. "Efficient Heterogeneous Copper-Catalysed C–Se Coupling of Aryl Iodides with Symmetrical Diselenides towards Unsymmetrical Monoselenides." Journal of Chemical Research 42, no. 11 (November 2018): 584–88. http://dx.doi.org/10.3184/174751918x15409874473285.

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A highly efficient heterogeneous copper(I)-catalysed C–Se coupling of aryl iodides with diaryl diselenides was achieved in dimethylformamide at 110 °C under neutral conditions by using a 10 mol% of bipyridine-functionalised MCM-41-supported copper(I) complex [bpy-MCM-41-CuI] as the catalyst and magnesium as the reductive reagent, yielding a variety of unsymmetrical diaryl selenides in good to excellent yields. This heterogeneous copper catalyst can be easily recovered by a simple filtration of the reaction solution and recycled at least seven times without significant loss of activity.

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49

Govender, Alisa, Abdul Mahomed, and Holger Friedrich. "Water: Friend or Foe in Catalytic Hydrogenation? A Case Study Using Copper Catalysts." Catalysts 8, no. 10 (October 19, 2018): 474. http://dx.doi.org/10.3390/catal8100474.

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Copper oxide supported on alumina and copper chromite were synthesized, characterized, and subsequently tested for their catalytic activity toward the hydrogenation of octanal. Thereafter, the impact of water addition on the conversion and selectivity of the catalysts were investigated. The fresh catalysts were characterized using X-ray diffraction (XRD), BET surface area and pore volume, SEM, TEM, TGA-DSC, ICP, TPR, and TPD. An initial catalytic testing study was carried out using the catalysts to optimize the temperature and the hydrogen-to-aldehyde ratio—which were found to be 160 °C and 2, respectively—to obtain the best conversion and selectivity to octanol prior to water addition. Water impact studies were carried out under the same conditions. The copper chromite catalyst showed no deactivation or change in octanol selectivity when water was added to the feed. The alumina-supported catalyst showed no change in conversion, but the octanol selectivity improved marginally when water was added.

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50

Hall, J. B., and J. K. Kouba. "Electron Microscopy of Barium-Promoted Copper Chromite." Proceedings, annual meeting, Electron Microscopy Society of America 43 (August 1985): 390–91. http://dx.doi.org/10.1017/s0424820100118825.

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Copper chromite was reported as an effective catalyst for the hydrogenation of esters to alcohols by Homer Adkins in 1931, and it still remains the catalyst of choice for this reaction. Its most common commercial application is in the hydrogenation of fatty esters to detergent range linear alcohols. Typical reaction conditions are relatively severe: 200-250°C and 2000-4000 psig hydrogen. Barium is often used as a promoter and such a catalyst is prepared by codeposition of barium and copper chromates followed by calcination to the mixed chromite. The catalyst is usually activated by reduction with hydrogen which is believed to generate highly dispersed copper metal. The barium supposedly retards overreduction of the catalyst and ameliorates sulfate poisoning.Knowledge of the distribution and association of the Ba, Cu, and Cr catalyst components is important in understanding its function and in the design of better catalysts.

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Journal articles on the topic 'Copper catalysi'

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