Artykuły w czasopismach: „CO oxidation reaction”

1

Zhou, Xue-Fei, i 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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Ma, Guoyan, Le Wang, Xiaorong Wang, Lu Li i Hongfei Ma. "CO Oxidation over Alumina-Supported Copper Catalysts". Catalysts 12, nr 9 (10.09.2022): 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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Eid, Kamel, Yahia Ahmad, Assem Mohamed, Anas Elsafy i 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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Feitelberg, Alan S., i Sanjay M. Correa. "The Role of Carbon Monoxide in NO2 Plume Formation". Journal of Engineering for Gas Turbines and Power 122, nr 2 (3.01.2000): 287–92. http://dx.doi.org/10.1115/1.483215.

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Through a series of computational studies, carbon monoxide has been identified as an important promoter of NO oxidation to NO2 in combustion turbine exhaust gas at intermediate temperatures (450 to 750°C). NO2 formation is accompanied by enhanced CO burnout at these temperatures. Perfectly stirred reactor and plug flow reactor calculations indicate that concentrations of CO as low as 50 ppmv in exhaust gas containing 25 ppmv NO can result in the conversion of 50 percent of the NO to NO2 in less than 1 s. NO2 concentrations as low as 15 ppmv can result in visible, yellow-brown plumes from large diameter exhaust stacks. If NO2 plumes are to be prevented, then designers of gas turbines and heat recovery steam generators need to be aware of the relationships between time, temperature, and composition which cause NO2 to form in exhaust gas. Reaction path analysis indicates that the mutually promoted oxidation of CO and NO occurs through a self-propagating, three-step chain reaction mechanism. CO is oxidized by OH CO+OH→CO2+H, while NO is oxidized by HO2:NO+HO2→NO2+OH. In a narrow temperature range, the H-atom produced by the first reaction can react with O2 in a three body reaction to yield the hydroperoxy radical needed in the second reaction: H+O2+M→HO2+M, where M is any third body. The observed net reaction is CO+O2+NO→CO2+NO2, which occurs stoichiometrically at temperatures below about 550°C. As the temperature increases, additional reaction pathways become available for H, HO2, and OH which remove these radicals from the chain and eventually completely decouple the oxidation of CO from NO. An abbreviated set of elementary chemical reactions, including 15 species and 33 reactions, has been developed to model CO-enhanced oxidation of NO to NO2. This reaction set was derived from a larger reaction set with more than 50 species and 230 elementary chemical reactions, and was validated by comparison of PSR and PFR calculations using the two sets. [S0742-4795(00)01402-2]

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Dosa, Melodj, Miguel Jose Marin-Figueredo, Enrico Sartoretti, Chiara Novara, Fabrizio Giorgis, Samir Bensaid, Debora Fino, Nunzio Russo i Marco Piumetti. "Cerium-Copper Oxides Synthesized in a Multi-Inlet Vortex Reactor as Effective Nanocatalysts for CO and Ethene Oxidation Reactions". Catalysts 12, nr 4 (23.03.2022): 364. http://dx.doi.org/10.3390/catal12040364.

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In this study, a set of CuCeOx catalysts was prepared via the coprecipitation method using a Multi-Inlet Vortex Reactor: the Cu wt.% content is 5, 10, 20, 30 and 60. Moreover, pure CeO2 and CuO were synthesized for comparison purposes. The physico-chemical properties of this set of samples were investigated by complementary techniques, e.g., XRD, N2 physisorption at −196 °C, Scanning Electron Microscopy, XPS, FT-IR, Raman spectroscopy and H2-TPR. Then, the CuCeOx catalysts were tested for the CO and ethene oxidation reactions. As a whole, all the prepared samples presented good catalytic performances towards the CO oxidation reaction (1000 ppm CO, 10 vol.% O2/N2): the most promising catalyst was the 20%CuCeOx (complete CO conversion at 125 °C), which exhibited a long-term thermal stability. Similarly, the oxidative activity of the catalysts were evaluated using a gaseous mixture containing 500 ppm C2H4, 10 vol.% O2/N2. Accordingly, for the ethene oxidation reaction, the 20%CuCeOx catalyst evidenced the best catalytic properties. The elevated catalytic activity towards CO and ethene oxidation was mainly ascribed to synergistic interactions between CeO2 and CuO phases, as well as to the high amount of surface-chemisorbed oxygen species and structural defects.

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Lin, Ken-Huang, Shin-Pon Ju, Jia-Yun Li i Hsin-Tsung Chen. "The CO oxidation mechanism on the W(111) surface and the W helical nanowire investigated by the density functional theory calculation". Physical Chemistry Chemical Physics 18, nr 4 (2016): 3322–30. http://dx.doi.org/10.1039/c5cp05681k.

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Mishchenko, Denis D., Zakhar S. Vinokurov, Tatyana N. Afonasenko, Andrey A. Saraev, Mikhail N. Simonov, Evgeny Yu Gerasimov i Olga A. Bulavchenko. "Insights into the Contribution of Oxidation-Reduction Pretreatment for Mn0.2Zr0.8O2−δ Catalyst of CO Oxidation Reaction". Materials 16, nr 9 (2.05.2023): 3508. http://dx.doi.org/10.3390/ma16093508.

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A Mn0.2Zr0.8O2−δ mixed oxide catalyst was synthesized via the co-precipitation method and studied in a CO oxidation reaction after different redox pretreatments. The surface and structural properties of the catalyst were studied before and after the pretreatment using XRD, XANES, XPS, and TEM techniques. Operando XRD was used to monitor the changes in the crystal structure under pretreatment and reaction conditions. The catalytic properties were found to depend on the activation procedure: reducing the CO atmosphere at 400–600 °C and the reaction mixture (O2 excess) or oxidative O2 atmosphere at 250–400 °C. A maximum catalytic effect characterized by decreasing T50 from 193 to 171 °C was observed after a reduction at 400 °C and further oxidation in the CO/O2 reaction mixture was observed at 250 °C. Operando XRD showed a reversible reduction-oxidation of Mn cations in the volume of Mn0.2Zr0.8O2−δ solid solution. XPS and TEM detected the segregation of manganese cations on the surface of the mixed oxide. TEM showed that Mn-rich regions have a structure of MnO2. The pretreatment caused the partial decomposition of the Mn0.2Zr0.8O2−δ solid solution and the formation of surface Mn-rich areas that are active in catalytic CO oxidation. In this work it was shown that the introduction of oxidation-reduction pretreatment cycles leads to an increase in catalytic activity due to changes in the origin of active states.

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Bzovska i 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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Arán-Ais, Rosa M., Francisco J. Vidal-Iglesias, Manuel J. S. Farias, José Solla-Gullón, Vicente Montiel, Enrique Herrero i Juan M. Feliu. "Understanding CO oxidation reaction on platinum nanoparticles". Journal of Electroanalytical Chemistry 793 (maj 2017): 126–36. http://dx.doi.org/10.1016/j.jelechem.2016.09.031.

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Oleksenko, Lyudmila, George Fedorenko, Igor Matushko, Nelly Maksymovych i 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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Han, Qiuwan, Dongyang Zhang, Jiuli Guo, Baolin Zhu, Weiping Huang i Shoumin Zhang. "Improved Catalytic Performance of Au/α-Fe2O3-Like-Worm Catalyst for Low Temperature CO Oxidation". Nanomaterials 9, nr 8 (3.08.2019): 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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Shi, Xue, Sumin Li, Bao Zhang, Jiao Wang, Xiaochen Xiang, Yifei Zhu, Ke Zhao i in. "The Regulation of O2 Spin State and Direct Oxidation of CO at Room Temperature Using Triboelectric Plasma by Harvesting Mechanical Energy". Nanomaterials 11, nr 12 (16.12.2021): 3408. http://dx.doi.org/10.3390/nano11123408.

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Oxidation reactions play a critical role in processes involving energy utilization, chemical conversion, and pollutant elimination. However, due to its spin-forbidden nature, the reaction of molecular dioxygen (O2) with a substrate is difficult under mild conditions. Herein, we describe a system that activates O2 via the direct modulation of its spin state by mechanical energy-induced triboelectric corona plasma, enabling the CO oxidation reaction under normal temperature and pressure. Under optimized reaction conditions, the activity was 7.2 μmol h−1, and the energy consumption per mole CO was 4.2 MJ. The results of kinetic isotope effect, colorimetry, and density functional theory calculation studies demonstrated that electrons generated in the triboelectric plasma were directly injected into the antibonding orbital of O2 to form highly reactive negative ions O2−, which effectively promoted the rate-limiting step of O2 dissociation. The barrier of the reaction of O2− ions and CO molecular was 3.4 eV lower than that of O2 and CO molecular. This work provides an effective strategy for using renewable and green mechanical energy to realize spin-forbidden reactions of small molecules.

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Liu, Shuo, Yuguo Wu, Chunshan Zhou, Jianming Wu i Yulong Zhang. "Study on the CO Formation Mechanism during Coal Ambient Temperature Oxidation". Energies 13, nr 10 (20.05.2020): 2587. http://dx.doi.org/10.3390/en13102587.

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The CO formation rules of coal were analyzed by a self-developed testing device under ambient temperature. The changes of functional groups caused by oxidation were obtained using Fourier-transform infrared spectroscopy (FTIR). The experimental results showed that CO was generated during the ambient temperature oxidation. The highest concentration level of CO could be 389 ppm. The methylene and aldehyde groups on the side chains were involved in the reaction. For the quantum mechanical approach, we employed the density functional theory with the 6–31 G (d, p) basis set. Density functional theory–based computations interpreted the possible reaction sites on a coal molecule by electronic static potential analysis. The rationality of the predicted reactions was also evaluated by transition state analysis and energy analysis. This research theoretically proved that coal could be oxidized to carbon monoxide under ambient temperatures and gave the possible reaction paths.

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Lee, Hak Beum, i Hyoung Lim Koh. "CO oxidation Reaction over copper metal oxide catalysts". Journal of the Korean Oil Chemists' Society 33, nr 1 (30.03.2016): 129–35. http://dx.doi.org/10.12925/jkocs.2016.33.1.129.

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Papadopoulos, Christos, Konstantinos Kappis, Joan Papavasiliou, John Vakros, Marcin Kuśmierz, Wojciech Gac, Yiannis Georgiou, Yiannis Deligiannakis i George Avgouropoulos. "Copper-promoted ceria catalysts for CO oxidation reaction". Catalysis Today 355 (wrzesień 2020): 647–53. http://dx.doi.org/10.1016/j.cattod.2019.06.078.

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Kong, De-Long, Jian-Xun Du, Wei-Ming Chu, Chun-Ying Ma, Jia-Yi Tao i 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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Obradović, Maja, i Snežana Gojković. "CO tolerant Pt/Ru0.7Ti0.3O2 nanocatalyst for hydrogen oxidation reaction". Zastita materijala 59, nr 2 (2018): 265–72. http://dx.doi.org/10.5937/zasmat1802265o.

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Zhang, Lanjun, Yujia Han, Dexin Xu, Qin Jiang, Haihui Xin, Chenhui Fu i Wenjing He. "Study on the Reaction Path of -CH3 and -CHO Functional Groups during Coal Spontaneous Combustion: Quantum Chemistry and Experimental Research". Energies 15, nr 13 (4.07.2022): 4891. http://dx.doi.org/10.3390/en15134891.

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Coal spontaneous combustion (CSC) is a disaster that seriously threatens safe production in coal mines. Revealing the mechanism of CSC can provide a theoretical basis for its prevention and control. Compared with experimental research is limited by the complexity of coal molecular structure, the quantum chemical calculation method can simplify the complex molecular structure and realize the exploration of the mechanism of CSC from the micro level. In this study, toluene and phenylacetaldehyde were used as model compounds, and the quantum chemical calculation method was adopted. The reaction processes of the methyl and aldehyde groups with oxygen were investigated with the aid of the Gaussian 09 software, using the B3LYP functional and the 6-311 + G(d,p) basis set and including the D3 dispersion correction. On this basis, the generation mechanisms of CO and CO2, two important indicator gases in the process of CSC, were explored. The calculation results show that the Gibbs free energy changes and enthalpy changes in the two reaction systems are both of negative values. Accordingly, it is judged that the reactions belong to spontaneous exothermic reactions. In the reaction processes, the activation energy of CO is less than that of CO2, indicating that CO is formed more easily in the above-two reaction processes. In addition, the variations in concentrations of important oxidation products (CO and CO2) and main active functional groups (such as methyl, carboxyl and carbonyl) with temperature were revealed through a low-temperature oxidation experiment. The experimental results verify the accuracy of the above quantum chemical reaction path. Moreover, it is also found that the generation mechanisms of CO and CO2 in coal samples with different metamorphic degrees are different. To be specific, for low-rank coal (HYH), CO and CO2 mainly come from the oxidation of alkyl side chains; for high-rank coal (CQ), CO is produced by the oxidation of alkyl side chains, and CO2 is attributed to the inherent oxygen-containing structure.

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Li, Wen Yan, Qiu Luan Chen, Wu Qin, Ning Wang i Jin Lin Lai. "Interaction of CO with CuO and CuO/graphene: Reactions Mechanism and the Formation of CO₂". Advanced Materials Research 354-355 (październik 2011): 279–85. http://dx.doi.org/10.4028/www.scientific.net/amr.354-355.279.

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CuO/graphene oxygen carrier models were built to investigate the reaction stoichiometry mechanism between the fuel gas CO and oxygen carrier CuO. The results show that the energy barrier of the single metal oxide CuO oxidation CO is 127.17kJ/mol, while energy barrier is only 42.64 kJ/ mol for the CuO/graphene. From the point view of chemical reaction dynamics, the oxidation activity of CuO/graphene much higher than single-metal oxide CuO, which indicate that graphene can improve the reaction performance of oxygen carrier. And analysis results for the oxidation of fuel gas CO has an important understanding of the process of scientific significance, and will promote the fundamental understanding and applications of the oxygen carrier CuO.

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Pola, Josef, Jaroslav Včelák i Zdeněk Chvátal. "Cw CO2 laser driven oxidation of some perhalogenocycloalkenes". Collection of Czechoslovak Chemical Communications 56, nr 2 (1991): 398–405. http://dx.doi.org/10.1135/cccc19910398.

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The title reaction of hexafluorocyclobutene, 1,2-dichloro-3,3,4,4-tetrafluorocyclobutene and decafluorocyclohexene studied at total pressure 13.3 and 16 kPa yield oxalyl halides COX.COX (X = F, Cl) and C2F4 that undergo consecutive reactions to COF2, CO and X2. The oxidation of decafluorocyclohexene is preceded by retro-Diels-Alder decomposition affording hexafluorocyclobutene and C2F4. Two alternative mechanisms for the oxidation of the cyclobutenes are presented, one involving a novel cleavage of intermediary bicyclic dioxetanes. The decomposition of oxalyl fluoride into COF2 and CO is favored over its oxidation.

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Timmer, Phillip, Lorena Glatthaar, Tim Weber i Herbert Over. "Identifying the Active Phase of RuO2 in the Catalytic CO Oxidation Reaction, Employing Operando CO Infrared Spectroscopy and Online Mass Spectrometry". Catalysts 13, nr 8 (1.08.2023): 1178. http://dx.doi.org/10.3390/catal13081178.

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Operando diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) is combined with online mass spectrometry (MS) to help to resolve a long-standing debate concerning the active phase of RuO2 supported on rutile TiO2 (RuO2@TiO2) during the CO oxidation reaction. DRIFTS has been demonstrated to serve as a versatile probe molecule to elucidate the active phase of RuO2@TiO2 under various reaction conditions. Fully oxidized and fully reduced catalysts serve to provide reference DRIFT spectra, based on which the operando CO spectra acquired during CO oxidation under various reaction conditions are interpreted. Partially reduced RuO2@TiO2 was identified as the most active catalyst in the CO oxidation reaction. This is independent of the reaction conditions being reducing or oxidizing and whether the starting catalyst is the fully oxidized RuO2@TiO2 or the partially reduced RuO2@TiO2.

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Miller, Aleksandr, Vasily Kaichev, Igor Prosvirin i Valeriy Bukhtiyarov. "The Investigation of Catalytic Methanol Oxidation on Pt(111) and Pd(111) by X-Ray Photoelectron Spectroscopy and Mass-Spectrometry". Siberian Journal of Physics 4, nr 4 (1.12.2009): 31–41. http://dx.doi.org/10.54362/1818-7919-2009-4-4-31-41.

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Oxidation and dehydrogenation of methanol over Pt(111) and Pd(111) single-crystals were studied using in situ X-ray photoelectron spectroscopy (XPS) and mass-spectrometry. It was found that for both metals the methanol dehydrogenation proceeds via two routes: dehydrogenation to CO and hydrogen, and decomposition of methanol with C–O bond scission [1–3]. The rate of the second route is several times lower, however, carbon production in this case leads to formation of carbon deposits, which block the surface and hinder the catalytic reactions. Even in the presence of O2 in the gas phase, the main route of methanol conversion over Pd is dehydrogenation to CO and H2. Hydrogen is partially oxidized to water, and CO is oxidized to CO2. The reactions start at temperature above 450 K when surface carbon depositions are removed by oxygen. In contrast, over Pt in presence of O2, the main reaction products are CO2 and water. Reaction also starts above 450 K when the surface carbon deposits are removed. We suppose that the reaction comes via two stages: at first, methanol dehydrogenates to CO and H2, and then total oxidation of these intermediates occurs. At the same time we detected by in situ XPS the formation of formates on the Pt surface. It means that methanol over Pt partially oxidize via non-CO-involved route when the formation and following decomposition of surface formates lead to CO2 and H2 yield. The difference in product distribution over Pt and Pd in the methanol oxidation is in a good agreement with the fact that Pt is more active in the CO oxidation than Pd. In both cases, the active state in the methanol oxidation is Pt or Pd in the metallic state.

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Mo, Shengpeng, Qi Zhang, Yuhai Sun, Mingyuan Zhang, Jiaqi Li, Quanming Ren, Mingli Fu, Junliang Wu, Limin Chen i 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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Wang, Lei, Wu Qin, Xian Bin Xiao, Zong Ming Zheng, Jun Jiao Zhang, Chang Qing Dong i Yong Ping Yang. "Effect of Co-Doping on Iron-Based Oxygen Carrier for CO Oxidation in Chemical Looping Combustion". Advanced Materials Research 774-776 (wrzesień 2013): 725–28. http://dx.doi.org/10.4028/www.scientific.net/amr.774-776.725.

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This paper focuses on theoretical research of Co-doped Fe-based oxygen carrier for CO oxidation in chemical-looping combustion (CLC) system. Density functional theory (DFT) calculations were carried out to study of interaction between CO molecules and CoO/Fe2O3cluster, it is found that dissociation of O atom through breaking of Fe-O bonds in the Fe2O3system is the key step for CO oxidation reaction, and Low-fold O atoms in Fe2O3system could more readily dissociate from external surface. Moreover, the presence of CoO in Fe2O3could decrease activation energy and reaction energy of CO/Co-Fe2O3system, hence the reaction between CO and Fe2O3is promoted.

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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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Wang, Kejun, i Ping Zhong. "A kinetic study of Co oxidation over the perovskite-like oxide LaSrNio4". Journal of the Serbian Chemical Society 75, nr 2 (2010): 249–58. http://dx.doi.org/10.2298/jsc1002249w.

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The effect of reactant/product concentrations, reaction temperature and contact time on CO oxidation was investigated, using the perovskite-like oxide LaSrNiO4 as the catalyst. It was found that the reaction order of CO (reactant), as well as that of CO2 (product), is negative, the reaction orders for CO and CO2 being -0.32 and -0.51, respectively. However, the reaction order for O2 is positive, having a value of 0.62. The negative reaction order of CO and CO2 might be due to their competitive adsorption with O2, preventing the proceeding of oxygen dissociation (the rate-determining step of the reaction). The activation energy (Ea) of the reaction was calculated to be 49.3 kJ mol-1; this small activation energy suggests that LaSrNiO4 is a potential candidate for the CO oxidation reaction. The optimum weight hourly space velocity (WHSV) of the reaction was found to be 0.6 g s cm-3. The reaction conditions in the present case were (0.5-1 % CO + 0.5-2 % O2 + 0-2 % CO2), with He as the balance gas.

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KELLOGG, G. "The oxidation of rhodium field-emitter surfaces during the CO oxidation reaction". Journal of Catalysis 92, nr 1 (marzec 1985): 167–72. http://dx.doi.org/10.1016/0021-9517(85)90246-5.

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Wu, Zhang, Zhang, Duan, Li, Wei, Liu, Yuan, Wang i Hao. "New Insights into the Electrocatalytic Mechanism of Methanol Oxidation on Amorphous Ni-B-Co Nanoparticles in Alkaline Media". Catalysts 9, nr 9 (5.09.2019): 749. http://dx.doi.org/10.3390/catal9090749.

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Despite an increased interest in sustainable energy conversion systems, there have been limited studies investigating the electrocatalytic reaction mechanism of methanol oxidation on Ni-based amorphous materials in alkaline media. A thorough understanding of such mechanisms would aid in the development of amorphous catalytic materials for methanol oxidation reactions. In the present work, amorphous Ni-B and Ni-B-Co nanoparticles were prepared by a simple chemical reduction, and their electrocatalytic properties were investigated by cyclic voltammetry measurements. The diffusion coefficients (D0) for Ni-B, Ni-B-Co0.02, Ni-B-Co0.05, and Ni-B-Co0.1 nanoparticles were calculated to be 1.28 × 10−9, 2.35 × 10−9, 4.48 × 10−9 and 2.67 × 10−9 cm2 s−1, respectively. The reaction order of methanol in the studied transformation was approximately 0.5 for all studied catalysts, whereas the reaction order of the hydroxide ion was nearly 1. The activation energy (Ea) values of the reaction were also calculated for the Ni-B and Ni-B-Co nanoparticle systems. Based on our kinetic studies, a mechanism for the methanol oxidation reaction was proposed which involved formation of an electrocatalytic layer on the surface of amorphous Ni–B and Ni-B-Co nanoparticles. And methanol and hydroxide ions could diffuse freely through this three-dimensional porous conductive layer.

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Dobrosz-Gómez, Izabela, Miguel-Ángel Gómez-García i 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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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 (październik 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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Fan, Min Hui, Guan Qing Wang, Dan Luo, Ri Zan Li, Ning Ding i Jiang Rong Xu. "Characteristic of Low Calorific Fuel Gas Combustion in Porous Burner by Preheating Air". Applied Mechanics and Materials 624 (sierpień 2014): 361–65. http://dx.doi.org/10.4028/www.scientific.net/amm.624.361.

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The combustion characteristic of low calorific fuel gas was numerically investigated in porous burner by preheating air. Two-dimensional temperature profile, flame propagation precess, and CO reaction rate were analyzed detailly by preheating air, and compared with that of room air. The results showed that when the air is preheated, the combustion flame location locates to upstream, the maximum combustion temperature is higher than that of room air, and flame propagation velocity decreases.The CO oxidation reaction rate increases gradually with the radius distance increaing, but reaction region decreases. CO oxidation region guradually decreases and locates to the upstream with air preheating temperature increasing. Peaks of CO oxidation rate gradually change from two to one.

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Yu, Guo Xian, Qian Zhong, Mei Jin, Jin Huang Wang i Ping Lu. "Deep Desulfurization of Diesel Fuel Oxidized with TBHP Coupled with Solvent Extraction Intensified by Ultrasound". Advanced Materials Research 910 (marzec 2014): 57–60. http://dx.doi.org/10.4028/www.scientific.net/amr.910.57.

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Deep desulfurization of a hydrotreated diesel fuel was investigated with TBHP oxidation coupled with solvent extraction intensified by ultrasound. The process parameters for the oxidation desulfurization of diesel fuel, such as the type and dosage of catalyst, co-solvent, ultrasound time, molar ratio of TBHP and sulfur were investigated. The results showed that sulfur content of the hydrotreated diesel fuel was reduced from 140 ppm to 12 ppm with using 1%wt of sodium tungstate as catalyst, 20%wt of methanol as co-solvent during the reaction, reaction temperature at 90°C, ultrasound time for 15 min and TBHP/Sulfur molar ratio of 32, and ultrasound irradiation had the obvious reinforcement in oxidative desulfurization of diesel fuel.

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33

Yao, M., J. Qin i Z. Zheng. "Numerical study of the combustion mechanism of a homogeneous charge compression ignition engine fuelled with dimethyl ether and methane, with a detailed kinetics model". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 219, nr 10 (1.10.2005): 1213–23. http://dx.doi.org/10.1243/095440705x34810.

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The auto-ignition and combustion mechanisms of dimethyl ether (DME) in a fourstroke homogeneous charge compression ignition (HCCI) engine were investigated using a zero-dimensional thermodynamic model coupled with a detailed chemical kinetics model. The results indicate that DME displays two-stage auto-ignition, and heat release with a low-temperature reaction and a high-temperature reaction (HTR). Heat release with the HTR can be separated into two stages: blue flame and hot flame. HCCI ignition is controlled by hydrogen peroxide (H2O2) decomposition, and OH plays a very important role in HCCI combustion. Formaldehyde (CH2O) is the main source of H2O2. Based on the sensitivity analysis of chemical reactions, the major paths of the DME reaction occurring in the engine cylinder are clarified. The major paths of the DME reaction is H-atom abstraction from DME, followed by the first addition of O2 and second addition of O2, and then oxidation to formaldehyde (CH2O), the formyl radical (HCO), and finally carbon monoxide (CO). CO oxidation occurs at the hot flame by the elementary reaction CO + OH = CO2 + H. At leaner DME concentrations, CO cannot be completely converted to carbon dioxide (CO2), and the process will result in high CO emissions.

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Ko, Eun-Yong, Eun Duck Park, Kyung Won Seo, Hyun Chul Lee, Doohwan Lee i Soonho Kim. "Nanosized Pt-Co Catalysts for the Preferential CO Oxidation". Journal of Nanoscience and Nanotechnology 6, nr 11 (1.11.2006): 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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Banerjee, Sourav, Gowrav Munithimhaiah Narasimhaiah, Anish Mukhopadhyay i Atanu Bhattacharya. "CO Activation Determines Ultrafast Dynamics of CO Oxidation Reaction on Pd Nanoparticles". Journal of Physical Chemistry C 120, nr 45 (9.11.2016): 25806–21. http://dx.doi.org/10.1021/acs.jpcc.6b07719.

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UETSUKA, H., K. WATANABE, H. OHNUMA i K. KUNIMORI. "STRUCTURE-SENSITIVITY IN THE DYNAMICS OF CO OXIDATION OVER Pd SURFACES: INFRARED CHEMHEMILUMINESCENCE OF THE PRODUCT CO2". Surface Review and Letters 04, nr 06 (grudzień 1997): 1359–63. http://dx.doi.org/10.1142/s0218625x97001814.

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Infrared-chemiluminescence spectra of CO 2 molecules formed by steady-state CO oxidation on Pd (111), Pd (110), Pd (100) and polycrystalline- Pd surfaces have been measured to get information on the surface reaction dynamics. In all cases, the product CO 2 was vibrationally and rotationally excited. The CO 2 molecules desorbed from Pd (100) and Pd (111), which have flat surfaces, were vibrationally more excited than those from Pd (110) (stepped surface) and polycrystalline Pd . These results show that the dynamics of CO oxidation on Pd surfaces are structure-sensitive, i.e. the structure of the activated CO 2 complex depends on the surface structures of the reaction sites. Furthermore, the activities of steady-state CO oxidation as a function of surface temperature were different among these Pd surfaces, which indicates that the CO oxidation on Pd is also structure-sensitive in the kinetics.

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Fukusumi, Takanori, Natsuki Takei, Yubi Tateno, Takuya Aoki, Ai Ando, Kouhei Kozakai, Hiroko Shima i in. "Ene-thiol reaction of C3-vinylated chlorophyll derivatives in the presence of oxygen: synthesis of C3-formyl-chlorins under mild conditions". Journal of Porphyrins and Phthalocyanines 17, nr 12 (grudzień 2013): 1188–95. http://dx.doi.org/10.1142/s1088424613500983.

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Reactions of thiol with the C 3-vinyl group of various chlorophyll (Chl) derivatives were examined. The reactions resemble thiol-olefin co-oxidation, except that the vinyl C = C double bond was cleaved to afford a formyl group without any transition metal catalyst, and that the simple anti-Markovnikov adduct of thiol to olefin was obtained as a minor product. Peripheral substituents of Chl derivatives little affected the reaction, while the central metal atom of the chlorin macrocycle influenced the composition of the products. Oxygen and acid dissolved in the reaction mixture can facilitate the oxidation. Sufficiently mild conditions in this regioselective oxidation at the C 31-position are significant in bioorganic chemistry.

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38

Bowie, John H., Charles H. Depuy, Sally A. Sullivan i Veronica M. Bierbaum. "Gas-phase reactions of the hydroperoxide and peroxyformate anions". Canadian Journal of Chemistry 64, nr 6 (1.06.1986): 1046–50. http://dx.doi.org/10.1139/v86-175.

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The flowing afterglow technique has been used to study the reactions of HO2−and HC3− in the gas phase. The hydroperoxide ion reacts slowly with CO to form HO−, and oxidizes CO2, OCS, CS2, NO, SO2, CH3NCO, and CH3NCS in fast reactions to form CO3−, CO2S−, COS2−, NO2−, SO3−, CH3NCO2−, and CH3NCOS−, respectively. Reactions of HO2− with certain amides and esters provide synthetic routes for a number of interesting peracyl anions. One of these, the peroxyformate ion, HCO3−, reacts with CO and NO in slow oxidation reactions to form the formate ion HCO2−. It also forms HCO2− upon reaction with acetone and pivalaldehyde, perhaps by Baeyer–Villiger oxidation.

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39

Stamenkovic, Vojislav, Berislav Blizanac, Branimir Grgur i Nenad Markovic. "Electrocatalysis of fuel cells reaction on Pt and Pt-bimetallic anode catalysts: A selective review". Chemical Industry 56, nr 6 (2002): 273–86. http://dx.doi.org/10.2298/hemind0206273s.

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In this review we selectively summarize recent progress, primarily from our laboratory, in the development of interrelationships between the kinetics of the fuel cells reactions and the structure/composition of anode catalysts. The focus is placed on two types of metallic surfaces: platinum single crystals and bimetallic surfaces based on Pt. In the first part it was illustrated that the hydcogen reaction is structure sensitive process, with Pt(110) being an order of magnitude more active than either of the atomically "flatter" (100) and (111) surfaces. The hydrogen reaction on Pt(hkl) modified by pseudomorphic Pd (sub)monolayers shows the "volcano-like" behavior, having the maximum rate on Pt(111) modified by 1 ML of Pd. The Pt(111)-Pd system is used to demonstrate how the energetics of intermediates formed in the hydrogen reaction is affected by interfacial bonding and energetic constraints produced between pseudomorphic Pd films and the Pt(111) substrate. In the second part it was shown that the oxidation of Ha in the presence of CO occurs concurrently with CO oxidation on Pt and Pt bimetallic surfaces. The Pt-Ru system is used to demonstrate that both the bifunctional effect and the ligand effect contribute to the influence of Ru on the CO oxidation rate and for Hz oxidation process in the presence of CO. The knowledge is then used to create the real-life catalyst with the catalytic activities which are, to the greatest extend possible similar to the tailor-made surface.

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40

Ehsasi, M., S. Rezaie‐Serej, J. H. Block i K. Christmann. "Reaction rate oscillation of CO oxidation on Pt(210)". Journal of Chemical Physics 92, nr 12 (15.06.1990): 7596–609. http://dx.doi.org/10.1063/1.458197.

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Böttcher, A., H. Niehus, S. Schwegmann, H. Over i G. Ertl. "CO Oxidation Reaction over Oxygen-Rich Ru(0001) Surfaces". Journal of Physical Chemistry B 101, nr 51 (grudzień 1997): 11185–91. http://dx.doi.org/10.1021/jp9726899.

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Pandis, Pavlos K., Dimitris E. Perros i Vassilis N. Stathopoulos. "Doped apatite-type lanthanum silicates in CO oxidation reaction". Catalysis Communications 114 (sierpień 2018): 98–103. http://dx.doi.org/10.1016/j.catcom.2018.06.017.

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Freund, Hans-Joachim, Gerard Meijer, Matthias Scheffler, Robert Schlögl i Martin Wolf. "CO Oxidation as a Prototypical Reaction for Heterogeneous Processes". Angewandte Chemie International Edition 50, nr 43 (29.09.2011): 10064–94. http://dx.doi.org/10.1002/anie.201101378.

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Coney, Ciaran, Cristina Stere, Paul Millington, Agnes Raj, Sam Wilkinson, Michael Caracotsios, Geoffrey McCullough i in. "Spatially-resolved investigation of the water inhibition of methane oxidation over palladium". Catalysis Science & Technology 10, nr 6 (2020): 1858–74. http://dx.doi.org/10.1039/d0cy00154f.

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Pd/Al₂O₃ catalysts are known to be active for low temperature methane oxidation reactions, however it has been shown that gases normally associated with methane gas streams (H₂O, CO₂, H₂S) can have an inhibitory effect on the total oxidation reaction.

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45

Erasmus, Johannes, i Jeanet Conradie. "Oxidative addition of methyl iodide to [Rh(PhCOCHCOPh)(CO)(P(OCH2)3CCH3)]: an experimental and computational study". Open Chemistry 10, nr 1 (1.02.2012): 256–66. http://dx.doi.org/10.2478/s11532-011-0137-0.

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AbstractThe reaction rate of the oxidative addition and CO insertion steps of methyl iodide with [Rh(PhCOCHCOPh)(CO)(P(OCH2)3CCH3)] are presented. Large negative experimental values for the activation entropy and results from a density functional theory computational chemistry study indicated trans addition of the CH3I to [Rh(PhCOCHCOPh)(CO)(P(OCH2)3CCH3)]. A study of the molecular orbitals gives insight into the flow of electrons during the oxidative addition reaction. CO insertion leads to a square pyramidal [Rh(PhCOCHCOPh)(P(OCH2)3CCH3)(COCH3)(I)] acyl product with the COCH3 moiety in the apical position. The strong electron donation of the P(OCH2)3CCH3 ligand accelerates the oxidation addition step of methyl iodide to [Rh(PhCOCHCOPh)(CO)(P(OCH2)3CCH3)] by ca. 265 times faster (at 35°C) than that of the Monsanto catalyst, but inhibits the CO insertion step.

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46

Schubert, M. M., T. P. Häring, G. Bräth, H. A. Gasteiger i R. J. Behm. "New DRIFTS Cell Design for the Simultaneous Acquisition of IR Spectra and Kinetic Data Using On-Line Product Analysis". Applied Spectroscopy 55, nr 11 (listopad 2001): 1537–43. http://dx.doi.org/10.1366/0003702011953775.

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A new design for a DRIFTS (diffuse reflectance infrared Fourier transform spectrometry) cell for in situ studies in heterogeneous catalysis is presented, which allows for improved reaction control (i.e., gas flow, temperature, minimized background conversion) and for precise kinetic measurements via on-line gas analysis by a tandem-arranged gas chromatograph. Specifically, the very low background activity of the cell itself for CO and H2 oxidation makes it possible to study the preferential CO oxidation in H2-rich gases (PROX) at relevant reaction temperatures (150–350 °C) and reactant concentrations (≤1 kPa CO and O2). Comparison with results obtained in a quartz tube reactor shows excellent agreement with the reaction rates obtained in the DRIFTS cell. The improved performance of the new DRIFTS cell design is demonstrated by examining the influence of CO2 on the PROX reaction over a Au/Fe2O3 catalyst. The addition of CO2 to idealized reformate (varying CO and O2 partial pressures, 75 kPa H2, balance N2) significantly reduces both the CO oxidation rate and the selectivity of the PROX reaction on Au/α-Fe2O3 and strongly affects the frequency of the C–O stretch vibration of adsorbed CO due to CO2 coadsorption.

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Todorova, Totka, Petya Petrova i Yuri Kalvachev. "Catalytic Oxidation of CO and Benzene over Metal Nanoparticles Loaded on Hierarchical MFI Zeolite". Molecules 26, nr 19 (28.09.2021): 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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Peng, Anyang, Mayfair C. Kung, Robert R. O. Brydon, Matthew O. Ross, Linping Qian, Linda J. Broadbelt i Harold H. Kung. "Noncontact catalysis: Initiation of selective ethylbenzene oxidation by Au cluster-facilitated cyclooctene epoxidation". Science Advances 6, nr 5 (styczeń 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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Chen, Hao, Yun Liu, Fan Yang, Mingming Wei, Xinfei Zhao, Yanxiao Ning, Qingfei Liu, Yi Zhang, Qiang Fu i Xinhe Bao. "Active Phase of FeOx/Pt Catalysts in Low-Temperature CO Oxidation and Preferential Oxidation of CO Reaction". Journal of Physical Chemistry C 121, nr 19 (4.05.2017): 10398–405. http://dx.doi.org/10.1021/acs.jpcc.7b01392.

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Lee, Jyh-Wei, i Jenq-Gong Duh. "High-temperature MgO–C–Al refractories–metal reactions in high-aluminum-content alloy steels". Journal of Materials Research 18, nr 8 (sierpień 2003): 1950–59. http://dx.doi.org/10.1557/jmr.2003.0271.

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MgO–C–Al refractories were used in this study to evaluate high-temperature refractory–metal reactions with molten Fe–Mn–Al alloys. Dynamic reaction tests at 1570 °C and static reaction tests at 1500 °C and 1600 °C, respectively, were used. MgAl2O4 and Al4C3 phases were observed in the refractory bulk, and a large amount of protective MgAl2O4 phase formed due to the decomposition of Al4C3 phases on the refractory–metal reaction interface of the MgO–C–Al brick to retard the high-temperature attack of Fe–Mn–Al alloy melts. The oxygen partial pressure was substantially reduced by the oxidation of graphite in the MgO–C–Al brick during high-temperature test. This resulted in the nitridation of aluminum in molten Fe–Mn–Al alloy. White aluminum nitride (AlN) with the shape of whisker-like powder was formed and adhered to the surface of the MgO–C–Al brick. Aluminum was depleted from the Fe–Mn–Al alloy by nitridation or the oxidation reaction by CO gas. The alloy would also be carburized due to the absorption of CO gas or the reaction between aluminum and CO gas, which was produced by the oxidation of graphite in the MgO–C–Al refractory after static reaction test. It is argued that the MgO–C–Al refractory is not suitable to be used in the melting of Fe–Mn–Al alloys with high aluminum contents.

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