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Graphical abstract Mo edge of the tensely concerned MoS 2 (0 1 0) surface was found to be inactive in CO methanation through a previous study, on which the promoted effect of cobalt was thus investigated by replacing the surface Mo atoms with Co atoms in different ratios and positions. This study discusses the adsorption and reaction mechanism in detail to give a performance comparison corresponding to all considered surfaces and verify the Co promoted effect by deriving an optimal result. Highlights • Co is generally four coordinated with S to keep surface stability, which make S vacancies are easily created. • Co is incorporated by replacing surface Mo on Mo-edge. • The substituted ratios in 0.25, 0.50 in both ortho- and meta-position, and 0.75 were considered. • A ratio of 0.25 or 0.50 in ortho-position can exhibit the highest catalytic activities. Abstract In light of the good performance of Mo-based catalysts for sulfur-resistant CO methanation, we investigated the reaction mechanism over pure MoS 2 in a previous study, in which the Mo-edge from (0 1 0) surface of MoS 2 was found inactive due to the difficulty in S-vacancy creation. It was generally recognized that Co is a good additive on Mo-based catalyst for CO methanation. Thus, we focused on promoting the Mo-edge by presenting a group of cobalt substituted surface models via DFT simulation. These models were all reconstructed by performing a thermodynamic investigation on the numbers of the created S-vacancies according to the reaction condition of CO methanation from experimental data. Based on the discussion of reaction pathways over four determined surfaces, we found that a substitute ratio of 0.25 and 0.50 in ortho-position can exhibit the highest catalytic activities, but a substitute ratio of 0.50 in meta-position exhibits the optimum stability in the overall reaction. [ABSTRACT FROM AUTHOR]

The supported Ni-based catalyst is widely used in the methanation process. Nevertheless, the major disadvantages of this catalyst are a poor behavior in the water-gas-shift ( WGS) reaction and the deactivation at higher temperatures. A new kind of catalyst, nickel-containing oxides catalyst (NiMgAl), obtained from thermal treatment of hydrotalcite-like compounds (HTlcs) was prepared using the co-precipitation method. The performance of this catalyst was systematically investigated and compared with that of the Ni/AlO catalyst. It was found that the NiMgAl catalyst shows an enhanced methanation activity compared to that of the Ni/AlO catalyst and the former catalyst shows a better performance for the methanation especially at temperature over 550°C. Three NiMgAl catalysts with different nickel content were prepared and tested in the methanation operated at a GHSV of 15000 h and n(H)/n(CO) of 1.5. The results indicate that with the NiMg8 catalyst a higher activity and stability could be achieved than with the NiMg5 and NiMg6 samples, the effect mainly attributed to a higher extent of Ni dispersion was confirmed by XRD results. [ABSTRACT FROM AUTHOR]

The process of dimethyl oxalate synthesis via CO gaseousphasecoupling reaction involves two reactions: CO coupling reaction toproduce dimethyl oxalate and the regeneration of methyl nitrite. Thesetwo reactions are mutually cycled, and matching reaction rates ofboth reactions are required. For this purpose, both reactions needto be simulated to provide guidance for scaling up the process. Inthis paper, the kinetics of methyl nitrite synthesis from NO, NO2, and methanol at atmospheric pressure was obtained by usinga stirred reactor. Based on this kinetics equation and mass transfer,a mathematical model for methyl nitrite regeneration reaction fromO2, NO, and methanol in a packed bubble column reactorwas proposed. Using this model, the effects of reaction temperature,N2volume fraction, NO/O2molar ratio, and superficialgas velocity on the methyl nitrite yield were predicted and comparedwith experimental results. It was found that the model predictionsagreed well with experimental data. [ABSTRACT FROM AUTHOR]