Zeitschriftenartikel: „Reaction of catalytic CO oxidation“

1

Zhou, Xue-Fei, und Jing Liu. „Co(salen) catalysed oxidation of synthetic lignin-like polymer: Co(salen) effects“. Chemical Industry 66, Nr. 5 (2012): 685–92. http://dx.doi.org/10.2298/hemind120124031z.

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In this paper, Co(salen) [salen = N, N?-bis(salicylidene)ethylenediamine] complex was studied as oxygen activators for the catalytic oxidation of a lignin model polymer using water as the solvent, with molecular oxygen and hydrogen peroxide as the oxidants. The effect of Co(salen) on oxidation was tested by spectroscopic methods (FTIR, 13C-NMR and GC-MS). The reactions catalysed by Co(salen) included C?-alcohol oxidation, C?-C? side chain cleavage, demethoxylation, aromatic ring cleavage, and ?-O-4 cleavage. In addition to the mechanistic information obtained, the effect of Co(salen) suggests that Co(salen) can be important for the catalytic oxidation, as they affect the oxidation of lignin model polymer. The reaction performed in the presence of Co(salen) was more efficient than without it. The formation of aldehyde in the catalytic oxidation, as shown by GC-MS, could be identified as the mechanism of oxidative cleavage of the ?-O-4 bonds.

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Bzovska und Mryglod. „Chemical oscillations in catalytic CO oxidation reaction“. Condensed Matter Physics 13, Nr. 3 (2010): 34801. http://dx.doi.org/10.5488/cmp.13.34801.

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3

Al Soubaihi, Rola Mohammad, Khaled Mohammad Saoud, Myo Tay Zar Myint, Mats A. Göthelid und Joydeep Dutta. „CO Oxidation Efficiency and Hysteresis Behavior over Mesoporous Pd/SiO2 Catalyst“. Catalysts 11, Nr. 1 (16.01.2021): 131. http://dx.doi.org/10.3390/catal11010131.

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Carbon monoxide (CO) oxidation is considered an important reaction in heterogeneous industrial catalysis and has been extensively studied. Pd supported on SiO2 aerogel catalysts exhibit good catalytic activity toward this reaction owing to their CO bond activation capability and thermal stability. Pd/SiO2 catalysts were investigated using carbon monoxide (CO) oxidation as a model reaction. The catalyst becomes active, and the conversion increases after the temperature reaches the ignition temperature (Tig). A normal hysteresis in carbon monoxide (CO) oxidation has been observed, where the catalysts continue to exhibit high catalytic activity (CO conversion remains at 100%) during the extinction even at temperatures lower than Tig. The catalyst was characterized using BET, TEM, XPS, TGA-DSC, and FTIR. In this work, the influence of pretreatment conditions and stability of the active sites on the catalytic activity and hysteresis is presented. The CO oxidation on the Pd/SiO2 catalyst has been attributed to the dissociative adsorption of molecular oxygen and the activation of the C-O bond, followed by diffusion of adsorbates at Tig to form CO2. Whereas, the hysteresis has been explained by the enhanced stability of the active site caused by thermal effects, pretreatment conditions, Pd-SiO2 support interaction, and PdO formation and decomposition.

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Oleksenko, Lyudmila, George Fedorenko, Igor Matushko, Nelly Maksymovych und Inna Vasylenko. „Perspectives for usage of adsorption semiconductor sensors based on Pd/SnO2 in environmental monitoring of carbon monoxide and methane emission“. E3S Web of Conferences 280 (2021): 06003. http://dx.doi.org/10.1051/e3sconf/202128006003.

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Nanosized semiconductor sensor materials based on SnO2 with different palladium contents were obtained via zol-gel technology with the use of ethylene glycol and hydrate of tin (VI) chloride as precursors. Morphology and phase composition of nanosized sensor materials were studied by X-ray diffraction and TEM methods. Catalytic activities of the Pd/SnO2 nanomaterials in the reaction of H2 and CO oxidation were investigated. Adsorption semiconductor sensors based on Pd/SnO2 nanomaterials were made by their calcination up to 620 0C in air and the sensors were found to be highly sensitive to presence of CO and CH4 in air ambient. Higher responses to CO of Pd-containing sensors in comparison with their responses to CH4 were confirmed by higher reaction activity of CO in catalytic oxidation reaction. Differences in sensitive properties of the sensors to methane and carbon monoxide were explained by features of the catalytic reactions of methane and carbon monoxide oxidation occurring on surfaces of the gas sensitive layers of the sensors.

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Dobrosz-Gómez, Izabela, Miguel-Ángel Gómez-García und Jacek Michał Rynkowski. „The Origin of Au/Ce1-xZrxO2 Catalyst’s Active Sites in Low-Temperature CO Oxidation“. Catalysts 10, Nr. 11 (13.11.2020): 1312. http://dx.doi.org/10.3390/catal10111312.

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Gold catalysts have found applications in many reactions of both industrial and environmental importance. Great interest has been paid to the development of new processes that reduce energy consumption and minimize pollution. Among these reactions, the catalytic oxidation of carbon monoxide (CO) is an important one, considering that a high concentration of CO in the atmosphere creates serious health and environmental problems. This paper examines the most important achievements and conclusions arising from the own authorship contributions concerning (2 wt. % Au)/Ce1−xZrxO2 catalyst’s active sites in low-temperature CO oxidation. The main findings of the present review are: (1) The effect of preparing conditions on Au crystallite size, highlighting some of the fundamental underpinnings of gold catalysis: the Au surface composition and the poisoning effect of residual chloride on the catalytic activity of (2 wt. % Au)/Ce1−xZrxO2 catalysts in CO oxidation; (2) The identification of ion clusters related to gold and their effect on catalyst’ surface composition; (3) The importance of physicochemical properties of oxide support (e.g., its particle size, oxygen mobility at low temperature and redox properties) in the creation of catalytic performance of Au catalysts; (4) The importance of oxygen vacancies, on the support surface, as the centers for oxygen molecule activation in CO reaction; (5) The role of moisture (200–1000 ppm) in the generation of enhanced CO conversion; (6) The Au-assisted Mars-van Krevelen (MvK) adsorption–reaction model was pertinent to describe CO oxidation mechanism. The principal role of Au in CO oxidation over (2 wt. % Au)/Ce1−xZrxO2 catalysts was related to the promotion in the transformation process of reversibly adsorbed or inactive surface oxygen into irreversibly adsorbed active species; (7) Combination of metallic gold (Au0) and Au-OH species was proposed as active sites for CO adsorption. These findings can help in the optimization of Au-containing catalysts.

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Eid, Kamel, Yahia Ahmad, Assem Mohamed, Anas Elsafy und Siham Al-Qaradawi. „Versatile Synthesis of Pd and Cu Co-Doped Porous Carbon Nitride Nanowires for Catalytic CO Oxidation Reaction“. Catalysts 8, Nr. 10 (22.09.2018): 411. http://dx.doi.org/10.3390/catal8100411.

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Developing efficient catalyst for CO oxidation at low-temperature is crucial in various industrial and environmental remediation applications. Herein, we present a versatile approach for controlled synthesis of carbon nitride nanowires (CN NWs) doped with palladium and copper (Pd/Cu/CN NWs) for CO oxidation reactions. This is based on the polymerization of melamine by nitric acid in the presence of metal-precursors followed by annealing under nitrogen. This intriguingly drove the formation of well-defined, one-dimensional nanowires architecture with a high surface area (120 m2 g−1) and doped atomically with Pd and Cu. The newly-designed Pd/Cu/CN NWs fully converted CO to CO2 at 149 °C, that was substantially more active than that of Pd/CN NWs (283 °C) and Cu/CN NWs (329 °C). Moreover, Pd/Cu/CN NWs fully reserved their initial CO oxidation activity after 20 h. This is mainly attributed to the combination between the unique catalytic properties of Pd/Cu and outstanding physicochemical properties of CN NWs, which tune the adsorption energies of CO reactant and reaction product during the CO oxidation reaction. The as-developed method may open new frontiers on using CN NWs supported various noble metals for CO oxidation reaction.

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Mahmood, Asif, Shahid M. Ramay, Yousef Al-Zeghayer, Sajjad Haider, Muhammad Ali Shar und Yasir Khalid. „Thermal Treatment Effect on Catalytic Activity of Au/TiO₂ for CO Oxidation“. Applied Mechanics and Materials 548-549 (April 2014): 254–58. http://dx.doi.org/10.4028/www.scientific.net/amm.548-549.254.

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A novel and well-organized study for the synthesis and enhanced catalytic activity of Au/TiO2catalysts has been developed. A momentous improvement in the catalytic activity of Au/TiO2in CO oxidation and preferential oxidation reaction by thermal treatment has been studied. Au/TiO2catalyst (Au (1 wt.%) supported on TiO2) was prepared by conventional deposition-precipitation method with NaOH followed by washing, drying and calcination in air at 400 °C for 4 h. Thermal treatment of Au/TiO2was performed at 450 °C under 0.05 mTorr. The activity of the catalysts has been examined in the reaction of CO oxidation and preferential oxidation (PROX) at 25-250 °C. The catalytic performance was found to be strongly affected by thermal treatment of the prepared catalyst prior to the reaction. Heat treatment after Au deposition has a positive effect on the CO oxidation performance. This is attributed to the introduction of a stronger interaction between the oxide and Au which improves the catalytic activity.

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Kappis, Konstantinos, Christos Papadopoulos, Joan Papavasiliou, John Vakros, Yiannis Georgiou, Yiannis Deligiannakis und George Avgouropoulos. „Tuning the Catalytic Properties of Copper-Promoted Nanoceria via a Hydrothermal Method“. Catalysts 9, Nr. 2 (01.02.2019): 138. http://dx.doi.org/10.3390/catal9020138.

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Copper-cerium mixed oxide catalysts have gained ground over the years in the field of heterogeneous catalysis and especially in CO oxidation reaction due to their remarkable performance. In this study, a series of highly active, atomically dispersed copper-ceria nanocatalysts were synthesized via appropriate tuning of a novel hydrothermal method. Various physicochemical techniques including electron paramagnetic resonance (EPR) spectroscopy, X-ray diffraction (XRD), N2 adsorption, scanning electron microscopy (SEM), Raman spectroscopy, and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) were employed in the characterization of the synthesized materials, while all the catalysts were evaluated in the CO oxidation reaction. Moreover, discussion of the employed mechanism during hydrothermal route was provided. The observed catalytic activity in CO oxidation reaction was strongly dependent on the nanostructured morphology, oxygen vacancy concentration, and nature of atomically dispersed Cu2+ clusters.

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LÓPEZ-CARREÑO, L. D. „EFFECTS OF FINITE REACTION RATES ON THE KINETIC PHASE TRANSITIONS IN THE CATALYTIC OXIDATION OF CARBON MONOXIDE“. Surface Review and Letters 09, Nr. 05n06 (Oktober 2002): 1735–39. http://dx.doi.org/10.1142/s0218625x02004311.

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Oxidation of carbon monoxide is one of the most extensively studied heterogeneous catalysis reactions, being important among other applications in automobile-emission control. Catalytic oxidation of carbon monoxide on platinum (111) surface was simulated by the Monte Carlo technique following an extended version of the model proposed by Ziff, Gulari and Barshad (ZGB). In the simulation, a simple square two-dimensional lattice of active sites replaces the surface of the catalyst. Finite reaction rates for (i) diffusion of the reactive species on the surface, (ii) reaction of a CO molecule with an oxygen atom in a nearest neighbor site, and (iii) desorption of unreacted CO molecules, have been taken into account. The produced CO 2 desorbs instantly. The average coverage of O, CO and the CO 2 production rate for a steady state configuration, as a function of the normalized CO partial pressure (P CO ), shows two kinetic phase transitions. In the ZGB model these transitions occur at P CO ≈ 0.39 and P CO ≈ 0.53. For 0.39 < P CO < 0.53 a reactive ( CO 2 production) steady state is found. Outside of the interval, the only steady state is a poisoned catalyst of pure CO or pure O. Our results show that finite reaction rates shift the values in which these phase transitions occur.

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Han, Qiuwan, Dongyang Zhang, Jiuli Guo, Baolin Zhu, Weiping Huang und Shoumin Zhang. „Improved Catalytic Performance of Au/α-Fe2O3-Like-Worm Catalyst for Low Temperature CO Oxidation“. Nanomaterials 9, Nr. 8 (03.08.2019): 1118. http://dx.doi.org/10.3390/nano9081118.

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The gold catalysts supported on various morphologies of α-Fe2O3 in carbon monoxide (CO) oxidation reaction have been studied for many researchers. However, how to improve the catalytic activity and thermal stability for CO oxidation is still important. In this work, an unusual morphology of α-Fe2O3 was prepared by hydrothermal method and gold nanoparticles were supported using a deposition-precipitation method. Au/α-Fe2O3 catalyst exhibited great activity for CO oxidation. The crystal structure and microstructure images of α-Fe2O3 were carried out by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and the size of gold nanoparticles was determined by transmission electron microscopy (TEM). X-ray photoelectron spectra (XPS) and Fourier transform infrared spectra (FTIR) results confirmed that the state of gold was metallic. The 1.86% Au/α-Fe2O3 catalyst calcined at 300 °C had the best catalytic performance for CO oxidation reaction and the mechanism for CO oxidation reaction was also discussed. It is highly likely that the small size of gold nanoparticle, oxygen vacancies and active sites played the decisive roles in CO oxidation reaction.

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Peng, Anyang, Mayfair C. Kung, Robert R. O. Brydon, Matthew O. Ross, Linping Qian, Linda J. Broadbelt und Harold H. Kung. „Noncontact catalysis: Initiation of selective ethylbenzene oxidation by Au cluster-facilitated cyclooctene epoxidation“. Science Advances 6, Nr. 5 (Januar 2020): eaax6637. http://dx.doi.org/10.1126/sciadv.aax6637.

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Traditionally, a catalyst functions by direct interaction with reactants. In a new noncontact catalytic system (NCCS), an intermediate produced by one catalytic reaction serves as an intermediary to enable an independent reaction to proceed. An example is the selective oxidation of ethylbenzene, which could not occur in the presence of either solubilized Au nanoclusters or cyclooctene, but proceeded readily when both were present simultaneously. The Au-initiated selective epoxidation of cyclooctene generated cyclooctenyl peroxy and oxy radicals that served as intermediaries to initiate the ethylbenzene oxidation. This combined system effectively extended the catalytic effect of Au. The reaction mechanism was supported by reaction kinetics and spin trap experiments. NCCS enables parallel reactions to proceed without the constraints of stoichiometric relationships, offering new degrees of freedom in industrial hydrocarbon co-oxidation processes.

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Mo, Shengpeng, Qi Zhang, Yuhai Sun, Mingyuan Zhang, Jiaqi Li, Quanming Ren, Mingli Fu, Junliang Wu, Limin Chen und Daiqi Ye. „Gaseous CO and toluene co-oxidation over monolithic core–shell Co3O4-based hetero-structured catalysts“. Journal of Materials Chemistry A 7, Nr. 27 (2019): 16197–210. http://dx.doi.org/10.1039/c9ta03750k.

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Gaseous CO co-existence could improve catalytic toluene oxidation over Co₃O₄-based catalysts, and the reaction mechanism on the CO/toluene oxidation may be mutually independent in the presence of both CO and toluene.

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Turaeva, N. „SIZE EFFECTS IN THE D-BAND MODEL OF CO OXIDATION BY GOLD NANOPARTICLES“. «Узбекский физический журнал» 20, Nr. 4 (21.07.2018): 236–42. http://dx.doi.org/10.52304/.v20i4.98.

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The volcano-type size dependence of the extraordinary catalytic activity of gold nanoparticles in CO oxidation is discussed on the basis of combination of the d-band model, the jellium model of metal clusters and the role of Fermi level in catalytic activity. The reaction rate depends non-monotonically upon the size of nanoparticles, due to exponential dependences of adsorption of reagents and desorption of products on the differences of the Fermi level of the metal cluster and antibonding states of CO and CO2 molecules forming chemical bonds with the nanoparticle, respectively. The origin of activation of the CO molecules towards the CO oxidation reaction by gold nanocatalysts is discussed in frame of the vibronic theory of chemical reactions based on the vibronic connection between charge transfer and nuclear processes.

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Kong, De-Long, Jian-Xun Du, Wei-Ming Chu, Chun-Ying Ma, Jia-Yi Tao und Wen-Hua Feng. „Ag/Pyridine Co-Mediated Oxidative Arylthiocyanation of Activated Alkenes“. Molecules 23, Nr. 10 (22.10.2018): 2727. http://dx.doi.org/10.3390/molecules23102727.

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An efficient Ag/pyridine co-mediated oxidative arylthiocyanation of activated alkenes via radical addition/cyclization cascade process was developed. This reaction could be carried out under mild conditions to provide biologically interesting 3-alkylthiocyanato-2-oxindoles in good to excellent yields. Mechanistic studies suggested a unique NCS• radical addition path and clarified the dual roles of catalytic pyridine as base and crucial ligand to accelerate the oxidation of Ag(I) to Ag(II), which is likely oxidant responsible for the formation of NCS• radical. These mechanistic results may impact the design and refinement of other radical based reactions proceeding through catalytic oxidations mediated by Ag(I)-pyridine/persulfate. The chemical versatility of thiocyanate moiety was also highlighted via SCN-tailoring chemistry in post-synthetic transformation for new S-C(sp3/sp2/sp), S-P, and S-S bonds constructions. The protocol provides an easy access to many important bioisosteres in medicinal chemistry and an array of sulfur-containing 2-oxindoles that are difficult to prepare by other approaches.

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Peng, Liwen, Haiwang Wang und Mengge Lv. „A Novel Preparation of Mn/NiCo2O4 Catalyst with High Catalytic Activity on Methane“. Journal of Nanoelectronics and Optoelectronics 16, Nr. 6 (01.06.2021): 926–32. http://dx.doi.org/10.1166/jno.2021.3029.

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In this paper, a Mn/NiCo2O4 catalyst was prepared for the complete oxidation of low-concentration methane. When the ratio of Mn: Co is 1:4, the catalyst has the best catalytic activity, and the best methane conversion temperature Feis 400 °C. In addition, the catalytic activity remains stable during the long-term reaction, showing adequate thermal stability. The catalyst is grown on FeCrAl alloy by hydrothermal method to complete the catalytic oxidation of methane. In the catalysis process, the Mn/NiCo2O4-FeCrAl catalyst is energized and the current is directly passed through the alloy substrate to generate Joule heat, reaching the optimal catalytic temperature for complete oxidation of methane.

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Ko, Eun-Yong, Eun Duck Park, Kyung Won Seo, Hyun Chul Lee, Doohwan Lee und Soonho Kim. „Nanosized Pt-Co Catalysts for the Preferential CO Oxidation“. Journal of Nanoscience and Nanotechnology 6, Nr. 11 (01.11.2006): 3567–71. http://dx.doi.org/10.1166/jnn.2006.17984.

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The preferential CO oxidation in the presence of excess hydrogen was studied over Pt-Co/γ-Al2O3. CO chemisorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectrometer (EDX) and temperature programmed reduction (TPR) were conducted to characterize active catalysts. The catalytic activity for CO oxidation and methanation at low temperatures increased with the amounts of cobalt in Pt-Co/γ-Al2O3. This accompanied the TPR peak shift to lower temperatures. The optimum molar ratio between Co and Pt was determined to be 10. The co-impregnated Pt-Co/γ-Al2O3 appeared to be superior to Pt/Co/γ-Al2O3 and Co/Pt/γ-Al2O3. The reductive pretreatment at high temperature such as 773 K increased the CO2 selectivity over a wide reaction temperature. The bimetallic phase of Pt-Co seems to give rise to high catalytic activity in selective oxidation of CO in H2-rich stream.

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Wu, Ke, Liang Zhou, Chun-Jiang Jia, Ling-Dong Sun und Chun-Hua Yan. „Pt-embedded-CeO2hollow spheres for enhancing CO oxidation performance“. Materials Chemistry Frontiers 1, Nr. 9 (2017): 1754–63. http://dx.doi.org/10.1039/c7qm00244k.

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Mohiuddin, A. K. M. „Development of Catalytic Converter Using Non-Precious Metals“. Advanced Materials Research 1115 (Juli 2015): 462–67. http://dx.doi.org/10.4028/www.scientific.net/amr.1115.462.

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This paper shows the uses of low cost metal for the development of catalytic converters. While bringing down the cost, attention must be paid on the performance capability of the catalytic converter. The objective of this work is to develop and design a low cost catalytic converter using copper as the main catalyst in the catalyst system. Copper powder was chosen as the alternative catalyst to reduce the use of precious group metals (PGMs) platinum, palladium, and rhodium. A spark ignition engine’s catalytic converter has to perform the oxidation of CO, oxidation of HC and reduction of NOxsimultaneously in order to satisfy its performance requirement. These three chemical reactions are taking place simultaneously in a three way catalytic converter. To investigate the chemical kinetics and fluid flow characteristics of a catalytic converter, simulations have been carried out using COMSOL. From COMSOL MULTIPHYSICS, catalytic converter’s velocity field and pressure distribution have been simulated. From COMSOL REACTION ENGINEERING LAB, NO and CO concentration from a catalytic converter kinetics model have been plotted. NO and CO conversion for different air to fuel ratio had shown that for rich mixture, NO reduction reaches its maximum but CO oxidation is at its minimum. In lean mixture, CO oxidation is at its maximum but NO reduction is at its minimum. Simulations have shown the actual characteristics of the catalytic converter performance. The flow throughout catalytic converter and the backpressure have successfully determined and the catalyst conversion efficiency also shown clearly.

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Petrov, L. A., J. Soria und R. Cataluna. „Influence of Copper on the Catalytic Activity of Supported Rhodium Catalysts in the Reactions of CO Oxidation and NO Reduction“. Eurasian Chemico-Technological Journal 4, Nr. 4 (01.07.2017): 265. http://dx.doi.org/10.18321/ectj543.

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The catalytic activity of Cu, Rh, and Rh/Cu, catalysts supported on Al2O3, CeO2 and CeO2/Al2O3 in reactions of CO oxidation and NO reduction has been studied in temperature-programmed regime. Addition of Cu to Rh catalysts decreases temperature at which 5 and 50% degree of conversion, while end of reaction temperature is not influenced by presence of Cu. The presence of Cu has positive effect on the activity of Rh containing catalysts in the low temperature region. Cu has noticeable promoting effect mainly for the catalytic activity in the reaction of CO oxidation and in smaller extent for the reaction of NO reduction. Preliminary redox treatment of the catalysts decreases the light off temperature in the reactions of CO oxidation and in NO reduction. Thermal treatment at temperatures up to 973 K does not have sensible effect on the catalytic activities of all studied catalysts. Calcination at 1073 K, however, strongly decreases the catalytic activity of Rh/Cu/CeO2/Al2O3 catalysts.

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Krishnan, Ranganathan, Shiuan-Yau Wu und Hsin-Tsung Chen. „Catalytic CO oxidation on B-doped and BN co-doped penta-graphene: a computational study“. Physical Chemistry Chemical Physics 20, Nr. 41 (2018): 26414–21. http://dx.doi.org/10.1039/c8cp04745f.

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The catalytic reaction of carbon monoxide oxidation on boron-doped and boron–nitrogen co-doped penta-graphene materials has been systematically studied by utilizing spin-polarized density functional theory (DFT) calculations.

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Dong, Feng, Yuan Guo, Dongyang Zhang, Baolin Zhu, Weiping Huang und Shoumin Zhang. „Gold Nanoparticles Supported on Urchin-Like CuO: Synthesis, Characterization, and Their Catalytic Performance for CO Oxidation“. Nanomaterials 10, Nr. 1 (27.12.2019): 67. http://dx.doi.org/10.3390/nano10010067.

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Gold catalysts have been studied in-depth due to their unique activities for catalytic CO oxidation. Supports have intrinsic motivation for the high activity of gold catalysts. Thermally stable urchin-like CuO microspheres, which are potential support for gold catalysts, were prepared by facile solution-method. Then gold nanoparticles were loaded on them by deposition-precipitation method. The obtained gold catalysts were characterized by SEM, XRD, TEM, BET, ICP, and XPS. Their catalytic activity for CO oxidation was also evaluated. TEM results revealed that the gold nanoparticles with small sizes were highly distributed on the CuO surface in Au1.0/CuO-300. XPS observations demonstrated that the gold species in Au1.0/CuO-300 was of metallic state. Among the as-prepared catalysts, the Au1.0/CuO-300 catalyst displayed the best performance for CO oxidation and achieved 100% CO oxidation at 80 °C. It kept 100% conversion for 20 h at a reaction temperature of 180 °C, and showed good reusability after three reaction-cycles. The possible catalytic mechanism of Au1.0/CuO-300 catalyst for CO oxidation was also briefly proposed.

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Mundschau, M., M. E. Kordesch, B. Rausenberger, W. Engel, A. M. Bradshaw und E. Zeitler. „The influence of surface defects on the catalytic reaction of submonolayer films observed by photoemission electron microscopy“. Proceedings, annual meeting, Electron Microscopy Society of America 48, Nr. 4 (August 1990): 268–69. http://dx.doi.org/10.1017/s0424820100174473.

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Defects on surfaces are known to greatly enhance the rate of many catalytic reactions. In some cases, the active sites in catalysis may reside only at defect sites. Surface defects are best characterized by microscopic techniques. It was demonstrated earlier that catalytic reactions can be followed using an ultra high vacuum version of a classical photoemission electron microscope. This technique can image submonolayer coverages because of the extreme sensitivity of photoemission to local work function.We report here studies on the catalytic oxidation of adsorbed CO on Pt which was followed in situ and in real time. For temperatures below 500 K and for partial pressure ratios of oxygen to CO of less than ∽ 10:1, an adsorbed layer of CO forms which effectively blocks the co-adsorption of oxygen.

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Palagin, Dennis, und Jonathan P. K. Doye. „CO oxidation catalysed by Pd-based bimetallic nanoalloys“. Physical Chemistry Chemical Physics 17, Nr. 42 (2015): 28010–21. http://dx.doi.org/10.1039/c5cp00889a.

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Density functional theory based global geometry optimization has been used to demonstrate the crucial influence of the geometry of the catalytic cluster on the energy barriers for the CO oxidation reaction over Pd-based bimetallic nanoalloys.

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Li, Jing-Jing, Bao-Lin Zhu, Gui-Chang Wang, Zun-Feng Liu, Wei-Ping Huang und Shou-Min Zhang. „Enhanced CO catalytic oxidation over an Au–Pt alloy supported on TiO2 nanotubes: investigation of the hydroxyl and Au/Pt ratio influences“. Catalysis Science & Technology 8, Nr. 23 (2018): 6109–22. http://dx.doi.org/10.1039/c8cy01642a.

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Fu, Zhi Dan, Qing Ye, Shui Yuan Cheng und Dao Wang. „Catalytic Oxidation of CO over Ag-Doped Manganese Oxide Catalysts: Preparation and Catalytic Activity“. Advanced Materials Research 1089 (Januar 2015): 133–36. http://dx.doi.org/10.4028/www.scientific.net/amr.1089.133.

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The manganese oxide (MnO2) sample was synthesized by the reaction of KMnO4 with Mn (Ac)2 using the HNO3 solution as pH regulator. The Ag-doped manganese oxide, Ag/MnO2-Q and Ag/MnO2-H, were synthesized by incorporation method and typical wet impregnation method, respectively. The structure of catalysts was characterized by N2 adsorption/desorption and X-ray diffraction. The influences of preparation methods on the catalytic activity of CO oxidation were studied. The doping of Ag to MnO2 decreased the specific surface area of Ag/MnO2 catalysts, especially for Ag/MnO2-H samples prepared by traditional wet-impregnation method. The Ag/MnO2 catalysts showed higher catalytic activity for CO oxidation than that of MnO2. The catalytic activities of Ag/MnO2 samples strongly depended upon the preparing methods, among which 3Ag/MnO2-Q catalyst, prepared by the incorporation method, was the most efficient catalyst towards the addressed reactions. The excellent performance of 3Ag/MnO2-Q was mainly associated with the good low-temperature reducibility, abundant surface oxygen and broadly dispersed silver oxides species.

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Suchorski, Y., I. Bespalov, J. Zeininger, M. Raab, M. Datler, P. Winkler und G. Rupprechter. „CO Oxidation on Stepped Rh Surfaces: μm-Scale Versus Nanoscale“. Catalysis Letters 150, Nr. 3 (13.09.2019): 605–12. http://dx.doi.org/10.1007/s10562-019-02950-0.

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Abstract The catalytic CO oxidation reaction on stepped Rh surfaces in the 10−6 mbar pressure range was studied in situ on individual μm-sized high-Miller-index domains of a polycrystalline Rh foil and on nm-sized facets of a Rh tip, employing photoemission electron microscopy (PEEM) and field-ion/field-emission microscopy (FIM/FEM), respectively. Such approach permits a direct comparison of the reaction kinetics for crystallographically different regions under identical reaction conditions. The catalytic activity of the different Rh surfaces, particularly their tolerance towards poisoning by CO, was found to be strongly dependent on the density of steps and defects, as well as on the size (µm vs. nm) of the respective catalytically active surface. Graphic Abstract

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PONG, W. Y., H. Y. CHANG, H. I. CHEN und J. R. CHANG. „CO-OXIDATION CATALYZED BY NANOCRYSTALLINE CeO2 PARTICLES WITH DIFFERENT MORPHOLOGIES“. Surface Review and Letters 15, Nr. 01n02 (Februar 2008): 123–31. http://dx.doi.org/10.1142/s0218625x0801110x.

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Nanocrystalline cerium oxide ( CeO 2) particles prepared by the novel two-stage precipitation method were used for the catalysis of CO oxidation. Firstly, two shapes, i.e. particulate (P-) and needle-like (N-), CeO 2 nanoparticles were formed via proposed temperature-arranged routes. The crystalline structure, morphology, particle size, and surface area of samples were characterized by using XRD, TEM, HRTEM, and BET techniques. Furthermore, the morphological effect of the CeO 2 samples on the catalytic activity of CO oxidation was investigated. From the experimental results, it indicated that the prepared samples were all nonporous and fcc-structured CeO 2. The CeO 2 particles, as precipitating at 90°C for 5 min and then aging at 90°C, were particulate, whereas they were needle-like by aging at 0°C. The CO oxidation reaction showed that the catalytic activity of N- CeO 2 nanoparticles was higher than that of P- CeO 2, attributing from the exposed higher-energy {100} and {110} facets for N- CeO 2 nanoparticles. Moreover, the calcined samples with higher degree of crystallinity showed further promotion in catalytic activity. It was also worthy to note, that by replacing the CeO 2 catalyst by Pd / CeO 2, a large increase in the CO conversion was found, especially catalyzed by Pd /N- CeO 2.

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Mouanni, Sihem, Tassadit Mazari, Sihem Benadji, Leila Dermeche, Catherine Marchal-Roch und Cherifa Rabia. „Simple and Green Adipic Acid Synthesis from Cyclohexanone and/or Cyclohexanol Oxidation with Efficient (NH4)xHyMzPMo12O40 (M: Fe, Co, Ni) Catalysts“. Bulletin of Chemical Reaction Engineering & Catalysis 13, Nr. 2 (11.06.2018): 386. http://dx.doi.org/10.9767/bcrec.13.2.1749.386-392.

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The oxidation of cyclohexanone and/or cyclohexanol to adipic acid (AA) was performed at 90 °C with a reaction time of 20 h, in the presence of H2O2 as oxidant and transition metal substituted ammonia polyoxometalates of formula, (NH4)xHyMzPMo12O40 (M: Fe, Co, or Ni, and x = 2.5 or 2.28) as catalysts. The catalytic results showed that the AA yield is sensitive to the transition metal nature and to the reaction conditions (sample weight and substrate amount). The (NH4)2.29H0.39Co0.16PMo12O40 was found to be the better catalytic system toward AA synthesis from cyclohexanone oxidation, with 40% of AA yield Copyright © 2018 BCREC Group. All rights reservedReceived: 12nd November 2017; Revised: 18th February 2018; Accepted: 19th February 2018; Available online: 11st June 2018; Published regularly: 1st August 2018How to Cite: Mouanni, S., Mazari, T., Benadji, S., Dermeche, L., Marchal-Roch, C., Rabia, C. (2018). Simple and Green Adipic Acid Synthesis from Cyclohexanone and/or Cyclohexanol Oxidation with Efficient (NH4)xHyMzPMo12O40 (M: Fe, Co, Ni) Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (2): 386-392 (doi:10.9767/bcrec.13.2.1749.386-392)

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Xamidov, Anvar, Farhodjon Hoshimov, Shavkat Mamatkulov, Khakimjan Butanov, Mirakhmat Yunusov und Olim Ruzimuradov. „Catalytic Activity of Ni, Co, Mo Supported Anodic Aluminum Oxide Nanocomposites“. Bulletin of Chemical Reaction Engineering & Catalysis 15, Nr. 3 (10.11.2020): 845–52. http://dx.doi.org/10.9767/bcrec.15.3.8480.845-852.

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Nanostructured catalysts based on porous aluminum oxide (PAO) and some 3d metals, such as: nickel, cobalt, and molybdenum, have been obtained by anodic oxidation and impregnation. The synthesis of porous aluminum oxide with a highly ordered pore structure with pore sizes of 50 nm and a thickness of 50 µm is carried out by the method of two-stage anodic oxidation. The catalysts are obtained by impregnation of 3d metals into nanosized pores of aluminum oxide. The obtained catalysts based on nickel and porous Al2O3 are studied by scanning electron microscopy (SEM-EDX). The results of SEM-EDX analysis shows that a spongy structure with filament sizes of 100 nanometers containing particles of 3d metals formed on the surface of the aluminum oxide matrix. The results are presented on the activity of nickel and heterogenic cobalt and molybdenum nanoparticles in the reaction of hydrogenation of hexene to hexane. The results show that the yield temperature of the hexane is decreased and the yield of hexane is observed at 200 °C with Ni/Al2O3 catalysts, and a similar yield of hexane mass is achieved at temperatures higher than 250 °C with Co-Mo/Al2O3 and traditional nickel catalysts on kieselguhr. Copyright © 2020 BCREC Group. All rights reserved

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Hu, Ting Ting, und Lin Hua Zhu. „Preparation of Gold Nanoparticles Supported on Montmorillonite and its Catalytic Activity for CO Oxidation“. Advanced Materials Research 955-959 (Juni 2014): 51–55. http://dx.doi.org/10.4028/www.scientific.net/amr.955-959.51.

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Gold catalysts supported on Na-MMT and Al-PILM noted as Au/Na-MMT and Au/Al-PILM respectively were prepared using Au(en)2Cl3 as precursor, and the catalytic oxidation activity for CO oxidation was investigated. The influence of different carriers on the conversion of CO was discussed. The phase of catalysts, the actual gold loading and the morphology of gold nanoparticles were characterized by X-ray diffraction(XRD), X-ray fluorescence analysis(XRF) and Transmission electron microscopy(TEM). The results showed that Au/Al-PILM exhibited higher catalytic activity for the oxidation reaction of CO, and 100% conversion of CO was achieved at reaction temperature of 250°C when gold precursor was loaded on the Al-PILM carrier at 60°Cand calcined it at 450°C for 1h.

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Leng, Xiaonan, Dantong Zhou, Tong Gao, Zhi Chen und Qiuming Gao. „Catalytic CO Oxidation over Au Nanoparticles Loaded Nanoporous Nickel Phosphate Composite“. Journal of Nanomaterials 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/528906.

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Au/nickel phosphate-5 (Au/VSB-5) composite with the noble metal loading amount of 1.43 wt.% is prepared by using microporous VSB-5 nanocrystals as the support. Carbon monoxide (CO) oxidation reaction is carried out over the sample with several catalytic cycles. Complete conversion of CO is achieved at 238°C over the catalyst at the first catalytic cycle. The catalytic activity improved greatly at the second cycle with the complete conversion fulfilled at 198°C and preserved for the other cycles. A series of experiments such as X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), ultraviolet-visible (UV-vis) spectroscopy, and X-ray photoelectron spectroscopy (XPS) are carried out to characterize the catalysts before and after the reaction to study the factors influencing this promotion at the second cycle.

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El-Shobaky, G. A., A. S. Ahmad, A. M. Ghozza und S. M. El-Khouly. „Surface and Catalytic Properties of γ-Irradiated Fe2O3/Al2O3 Solids“. Adsorption Science & Technology 13, Nr. 3 (Juni 1996): 153–63. http://dx.doi.org/10.1177/026361749601300302.

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Two specimens of Fe2O3/Al2O3 solids were prepared by impregnating a known mass of finely-powdered Al(OH)3 with calculated amounts of ferric nitrate solutions followed by drying at 120°C and calcination in air at 400°C for 4 h. The mixed solids thus prepared had the nominal molar compositions 0.06Fe2O3/Al2O3 and 0.125Fe2O3/Al2O3 (FeAl-I and FeAl-II). The surface and catalytic properties of various irradiated solids (15–200 Mrad) were studied using nitrogen adsorption at −196°C and catalysis of CO oxidation by O2 at 150–280°C using a static method. The results obtained revealed that γ-irradiation at doses between 15 and 80 Mrad resulted in a progressive decrease (7–22%) in the surface area of the treated solids. Treatment with doses above this limit exerted an opposite effect. γ-Irradiation also resulted in a widening of the pores of the irradiated adsorbents. The catalytic activity of the FeAl-I solid was influenced slightly by γ-rays while the FeAl-II catalyst was significantly modified by this treatment. The reaction rate constant per unit surface area of the catalytic reaction conducted at 280°C over the FeAl-II solid decreased (65%) by exposure to doses up to 120 Mrad, then increased on increasing the dose above this limit. This did not modify the mechanism of the catalytic reaction, but changed the number of catalytically-active sites taking part in chemisorption and catalysis of the CO oxidation reaction without affecting their energetic nature.

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Zhang, Xuejun, Min Zhao, Zhongxian Song, Heng Zhao, Wei Liu, Jinggang Zhao, Zi'ang Ma und Yun Xing. „The effect of different metal oxides on the catalytic activity of a Co3O4 catalyst for toluene combustion: importance of the structure–property relationship and surface active species“. New Journal of Chemistry 43, Nr. 27 (2019): 10868–77. http://dx.doi.org/10.1039/c9nj01783f.

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The Co–La catalyst was used to the catalytic oxidation of toluene. The LaCoO₃ perovskite was detected. The abundance of Co³⁺ and active oxygen contributed synergistically to the redox cycle reaction, which could improve the catalytic activity.

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Wang, Ying-Ying. „Theoretical study of the oxidation of formic acid on a PtPd(111) surface“. Progress in Reaction Kinetics and Mechanism 44, Nr. 1 (Februar 2019): 67–73. http://dx.doi.org/10.1177/1468678319830512.

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By performing density functional theory calculations, the adsorption configurations of formic acid and possible reaction pathway for HCOOH oxidation on PtPd(111) surface are located. Results show that CO2 is preferentially formed as the main product of the catalytic oxidation of formic acid. The formation of CO on the pure Pd surface could not possibly occur during formic acid decomposition on the PtPd(111) surface owing to the high reaction barrier. Therefore, no poisoning of catalyst would occur on the PtPd(111) surface. Our results indicate that the significantly increased catalytic activity of bimetallic PtPd catalyst towards HCOOH oxidation should be attributed to the reduction in poisoning by CO.

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Stefanov, Plamen K., Yuichi Ohno, Toshiro Yamanaka, Yoshiyuki Seimiya, Kazushi Kimura und Tatsuo Matsushima. „Reaction dynamics of catalytic CO oxidation on a Pt(113) surface“. Surface Science 416, Nr. 1-2 (Oktober 1998): 305–19. http://dx.doi.org/10.1016/s0039-6028(98)00616-5.

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Eichler, A., und J. Hafner. „Reaction channels for the catalytic oxidation of CO on Pt(111)“. Physical Review B 59, Nr. 8 (15.02.1999): 5960–67. http://dx.doi.org/10.1103/physrevb.59.5960.

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Eichler, A., und J. Hafner. „Reaction channels for the catalytic oxidation of CO on Pt(111)“. Surface Science 433-435 (August 1999): 58–62. http://dx.doi.org/10.1016/s0039-6028(99)00061-8.

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Böttcher, A., und H. Niehus. „The Role of Subsurface Oxygen in the Catalytic CO-Oxidation Reaction“. physica status solidi (a) 173, Nr. 1 (Mai 1999): 101–7. http://dx.doi.org/10.1002/(sici)1521-396x(199905)173:1<101::aid-pssa101>3.0.co;2-r.

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Saravanan, Govindachetty, Rohini Khobragade, Laxmi Chand Nagar und Nitin Labhsetwar. „Ordered intermetallic Pt–Cu nanoparticles for the catalytic CO oxidation reaction“. RSC Advances 6, Nr. 88 (2016): 85634–42. http://dx.doi.org/10.1039/c6ra19602k.

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Intermetallic platinum (Pt) nanoparticles using the abundantly available element copper (Pt₃Cu, PtCu, PtCu₃) with an average particle size of 4–5 nm on a γ-Al₂O₃ support were prepared to reduce the consumption of Pt for the removal of CO from gases.

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Smolin, Alexander V., Мikhail N. Mikhailov, Aleksey F. Gadzaov und Leonid M. Kustov. „Dynamics of Oxidation of Reduced Forms of CO2 under Electrochemical and Open-Сircuit Conditions on Polycrystalline Pt in H2CO3“. Metals 11, Nr. 2 (05.02.2021): 274. http://dx.doi.org/10.3390/met11020274.

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The problem of identifying correlations between catalytic and electrocatalytic processes is one of the fundamental problems of catalysis among “simple” organic substances, and the oxidation of CO and rCO2 is of great interest, since CO and CO2 are considered in pairs both during catalytic and electrocatalytic transformations. In the case of electrocatalysis, this analysis is important in the study of fuel cells. In this paper, we studied the correlation between the oxidation of reduced forms of CO2 (rCO2) under potentiodynamic-galvanoctatic electrochemical and open-circuit conditions of measurements on polycrystalline (pc)Pt in H2CO3. Periodic oscillations are revealed at the oxidation of Had and rCO2 on (pc)Pt. Quantum chemical calculations were carried out on the Pt13 cluster in order to identify the mechanisms of the rCO2 oxidation reaction. The correspondence in the energy parameters of the oxidation process of rCO2 under open-circuit conditions and electrochemical conditions is shown. The preliminary analysis of the system using density functional (DFT) calculations is carried out and the most stable systems that are based on Pt13 are found, namely rOH-Pt13-(CO)n, rOH-Pt13-(COH) and rOH-Pt13-(rCOOH). OH• species was chosen as the most likely candidate for the role of the oxidant for rCO2. Preliminary calculations for the expected reactions were carried out, and the optimal PES is revealed.

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Dey, Subhashish, Ganesh Chandra Dhal, Devendra Mohan und Ram Prasad. „Effect of Preparation Conditions on the Catalytic Activity of CuMnOx Catalysts for CO Oxidation“. Bulletin of Chemical Reaction Engineering & Catalysis 12, Nr. 3 (28.10.2017): 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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Zedan, Abdallah F., Safa Gaber, Amina S. AlJaber und Kyriaki Polychronopoulou. „CO Oxidation at Near-Ambient Temperatures over TiO2-Supported Pd-Cu Catalysts: Promoting Effect of Pd-Cu Nanointerface and TiO2 Morphology“. Nanomaterials 11, Nr. 7 (25.06.2021): 1675. http://dx.doi.org/10.3390/nano11071675.

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Significant improvement of the catalytic activity of palladium-based catalysts toward carbon monoxide (CO) oxidation reaction has been achieved through alloying and using different support materials. This work demonstrates the promoting effects of the nanointerface and the morphological features of the support on the CO oxidation reaction using a Pd-Cu/TiO2 catalyst. Pd-Cu catalysts supported on TiO2 were synthesized with wet chemical approaches and their catalytic activities for CO oxidation reaction were evaluated. The physicochemical properties of the prepared catalysts were studied using standard characterization tools including SEM, EDX, XRD, XPS, and Raman. The effects of the nanointerface between Pd and Cu and the morphology of the TiO2 support were investigated using three different-shaped TiO2 nanoparticles, namely spheres, nanotubes, and nanowires. The Pd catalysts that are modified through nanointerfacing with Cu and supported on TiO2 nanowires demonstrated the highest CO oxidation rates, reaching 100% CO conversion at temperature regime down to near-ambient temperatures of ~45 °C, compared to 70 °C and 150 °C in the case of pure Pd and pure Cu counterpart catalysts on the same support, respectively. The optimized Pd-Cu/TiO2 nanowires nanostructured system could serve as efficient and durable catalyst for CO oxidation at near-ambient temperature.

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Al Soubaihi, Rola, Khaled Saoud und Joydeep Dutta. „Critical Review of Low-Temperature CO Oxidation and Hysteresis Phenomenon on Heterogeneous Catalysts“. Catalysts 8, Nr. 12 (14.12.2018): 660. http://dx.doi.org/10.3390/catal8120660.

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There is a growing demand for new heterogeneous catalysts for cost-effective catalysis. Currently, the hysteresis phenomenon during low-temperature CO oxidation is an important topic in heterogeneous catalysis. Hysteresis provides important information about fluctuating reaction conditions that affect the regeneration of active sites and indicate the restoration of catalyst activity. Understanding its dynamic behavior, such as hysteresis and self-sustained kinetic oscillations, during CO oxidation, is crucial for the development of cost-effective, stable and long-lasting catalysts. Hysteresis during CO oxidation has a direct influence on many industrial processes and its understanding can be beneficial to a broad range of applications, including long-life CO2 lasers, gas masks, catalytic converters, sensors, indoor air quality, etc. This review considers the most recent reported advancements in the field of hysteresis behavior during CO oxidation which shed light on the origin of this phenomenon and the parameters that influence the type, shape, and width of the conversion of the hysteresis curves.

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Šmíd, Bretislav, Toshiyuki Mori, M. Takahashi, Ding Rong Ou, V. Matolín und Iva Matolínova. „Fabrication and Microanalysis of Nano-Structured CuO_X-CeO₂ Catalysts for CO Oxidation Reaction“. Advanced Materials Research 15-17 (Februar 2006): 261–66. http://dx.doi.org/10.4028/www.scientific.net/amr.15-17.261.

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Carbon monoxide (CO) is a significant air pollutant produced in incomplete oxidation of carbon in combustion. From the viewpoint of environmental protection, it is important that the concentration of CO gas is lowered in air. Catalysis is proving to be an effective route for removing this pollutant. Therefore, a design of nano-structured catalysts with high efficiency is required. In the present work, we focus on a development of nano-size CuOx-CeO2 catalysts for CO oxidation reaction. To prepare nano-structured Cu loaded CeO2 catalysts, a combined method of the conventional impregnation and ammonium carbonate co-precipitation was examined. Morphology, crystal phase and surface structure of prepared catalysts were characterized using High-Resolution Transmission Electron Microscopy (HRTEM), Scanning Electron Microscopy (SEM) and Powder X-ray Diffraction (XRD). Catalytic properties of CuOx-CeO2 for CO oxidation were investigated in gas flow reactor system under atmospheric pressure and compared with copper oxide loaded zinc oxide. We expected that nano-structured CuOx-CeO2 catalysts could be used for removing CO produced in a wet reforming reaction of fuel cell applications.

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Zhou, Xue-Fei. „Co(Salen) Catalysed Oxidation of Synthetic Lignin-Like Polymer: Naoh Effects“. Polish Journal of Chemical Technology 16, Nr. 3 (01.09.2014): 91–96. http://dx.doi.org/10.2478/pjct-2014-0057.

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Abstract An attempt has been made to selectively oxidise synthetic lignin-like polymer for fine chemicals. The G- and S-type polymers (G- and S- type lignin model polymers) were synthesized using simple aromatic compounds as starting materials and then oxidised to benzaldehydes by reacting them with Co(salen) catalytic system. The reaction was characterized by measuring the change of the polymer with FTIR, C-13 NMR and GC-MS spectroscopy. The results obtained by the FTIR and C-13 NMR showed that the effects of NaOH were important and higher yield of benzaldehydes characterized by GC-MS in the presence of NaOH in the course of catalytic oxidation of the polymer demonstrated these effects. From the results, the catalyst could suitably be used in green procedures for lignin transformation.

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Fang, Bin Zheng, Chen Liang Zhou, Jian Wei Cao, Na Zhang, Jia Li Han, Hui Li und Xi Dong Wang. „Octahedral Molecular Sieves (OMS) of Copper-Manganese Oxides for Low-Temperature Selective Catalytic Reduction of NO with CH₄“. Applied Mechanics and Materials 675-677 (Oktober 2014): 543–46. http://dx.doi.org/10.4028/www.scientific.net/amm.675-677.543.

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Cu-OMS catalyst reveals well catalytic performance on the oxidation-reduction reactions of gasoline engine exhaust. The catalysts were characterized by means of XRD, nitrogen physisorption and oxidation-reduction reactions. The results of the catalytic tests revealed that CO conversion can get 95% at as low as 150°C and achieve 100% at 200°C through 2CO+O2→2CO reaction, while CH4 and NO conversion can achieve 87% and 90% at 300°C respectively. The Cu-ML corresponds to a type IVisothermal, and Cu-OMS corresponds to a type II isothermal. High Cu dispersion in manganese oxide crystals and low agglomeration are the main reason for high activity.

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Yoshimaru, Shotaro, Masaaki Sadakiyo, Aleksandar Staykov, Kenichi Kato und Miho Yamauchi. „Modulation of the catalytic activity of Pt nanoparticles through charge-transfer interactions with metal–organic frameworks“. Chemical Communications 53, Nr. 50 (2017): 6720–23. http://dx.doi.org/10.1039/c7cc02829f.

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Ryzha, Iryna. „Modeling of carbon monoxide oxidation on the catalytic surface in the two-dimensional case“. Physico-mathematical modelling and informational technologies, Nr. 26 (30.12.2017): 83–89. http://dx.doi.org/10.15407/fmmit2017.26.083.

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A two-dimensional model of carbon monoxide (CO) catalytic oxidation on a platinum (Pt) surface for the Langmuir-Hinshelwood mechanism is investigated. The adsorbate-driven (1×1)-(1×2) structural phase transition of Pt(110) and the formation of new crystal planes on the catalytic surface (faceting) as well as the effect of the substrate temperature are taken into account. It is shown that the stability region for CO oxidation reaction changes when two dimensions are taken into account. Similarly to the one-dimensional case, the reaction of CO oxidation on Pt-catalyst surface is periodic in the stability region. Mixed-mode oscillations (MMO) for CO and oxygen (O) surface coverages as well as the fraction of the surface in the non-reconstructed (1×1)-state were found. Such behavior cannot be predicted by one-dimensional models when the equation for the change of degree of faceting is not taken into account.

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Stawowy, Michalina, Paulina Jagódka, Krzysztof Matus, Bogdan Samojeden, Joaquin Silvestre-Albero, Janusz Trawczyński und Agata Łamacz. „HKUST-1-Supported Cerium Catalysts for CO Oxidation“. Catalysts 10, Nr. 1 (12.01.2020): 108. http://dx.doi.org/10.3390/catal10010108.

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The synthesis method of metal–organic frameworks (MOFs) has an important impact on their properties, including their performance in catalytic reactions. In this work we report on how the performance of [Cu3(TMA)2(H2O)3]n (HKUST-1) and Ce@HKUST-1 in the reaction of CO oxidation depends on the synthesis method of HKUST-1 and the way the cerium active phase is introduced to it. The HKUST-1 is synthesised in two ways: via the conventional solvothermal method and in the presence of a cationic surfactant (hexadecyltrimethylammonium bromide (CTAB)). Obtained MOFs are used as supports for cerium oxide, which is deposited on their surfaces by applying wet and incipient wetness impregnation methods. To determine textural properties, structure, morphology, and thermal stability, the HKUST-1 supports and Ce@HKUST-1 catalysts are characterised using X-ray diffraction (XRD), N2 sorption, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). It is proven that the synthesis method of HKUST-1 has a significant impact on its morphology, surface area, and thermal stability. The synthesis method also influences the dispersion and the morphology of the deposited cerium oxide. Last but not least, the synthesis method affects the catalytic activity of the obtained material.

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Mihailova, Irena, und Dimitar Mehandjiev. „Catalytic activity of Co-åkermanite and Co-pyroxene in oxidation reactions“. Canadian Journal of Chemistry 89, Nr. 8 (August 2011): 939–47. http://dx.doi.org/10.1139/v11-061.

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Two calcium–cobalt silicates were synthesized in which cobalt occupies different structural positions. The crystal phases belong to two main structural silicate types. In the Co-åkermanite structure (Ca2CoSi2O7), cobalt cations take tetrahedral coordination toward oxygen atoms. In the Co-pyroxene structure of CaCoSi2O6, cobalt displays octahedral coordination. Ca2CoSi2O7 was prepared by solid-phase synthesis and CaCoSi2O6 was prepared by sol–gel method. The synthesis of the phases was confirmed by XRD, FTIR, and EPR data. On the basis of the XPS analysis, it can be concluded that Co2+ cations exist in the studied silicates. Thus, it is possible to study the catalytic activity of two silicate phases containing Co2+ cations in different coordinations: tetrahedral and octahedral. It was found that cobalt silicates with crystal structures corresponding to pyroxene and åkermanite possess catalytic activity in the reactions of complete oxidation of CO and toluene. Co-pyroxene exhibits higher catalytic activity than Co-åkermanite, but the higher cobalt content on the surface of Co-pyroxene should also be taken into account. Then, it turns out that catalytically active complexes with Со2+ ions in tetrahedral coordination are more efficient than those with such ions in octahedral coordination when equal concentrations of cobalt were used on the surface of the catalysts.

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