Theoretical insight into methanol steam reforming on indium oxide with different coordination environments  

作　　者：Jinglin Wang Haifeng Wang P.Hu 

机构地区：[1]Key Laboratory for Advanced Materials, Research Institute of Industrial Catalysis and Centre for Computational Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology [2]School of Chemistry and Chemical Engineering, The Queen's University of Belfast

出　　处：《Science China Chemistry》2018年第3期336-343,共8页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China(21333003,21622305);Young Elite Scientist Sponsorship Program by China Association for Science and Technology(YESS20150131);"Shu Guang"project supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundation(13SG30);the Fundamental Research Funds for the Central Universities(WJ616007)

摘　　要：Indium oxide(In_2O_3) has demonstrated to be an effective non-noble metal catalyst for methanol steam reforming reaction(MSR).However, the reaction mechanism of MSR and crucial structure-activity relations determining the catalytic performance of In_2O_3 are still not fully understood yet. Using density functional theory(DFT) calculation, we systematically investigate the MSR process over a high-index In_2O_3(211) and a favoured catalytic cycle of MSR is determined. The results show that In_2O_3(211) possesses excellent dehydrogenation and oxidizing ability, on which CH_3 OH can readily adsorb on the In4 c site and be easily activated by the reactive lattice oxygens, resulting in a total oxidation into CO_2 rather than CO, while the H_2 formation through surface H–H coupling limits the overall MSR activity because of the strong H adsorption on the two-coordinated lattice O(O_(2c)). Our analyses show that the relatively inert three-coordinated lattice O(O_(3c)) could play an important catalytic role. To uncover the influence of the local coordination of surface In atoms and lattice O on the catalytic activity, we evaluate the activity trend of several types of In_2O_3 surfaces including(211),(111), and(100) by examining the rate-limiting, which reveals the following activity order:(211)>(111)>(100). These findings provide an in-depth understanding on the MSR reaction mechanism over In_2O_3 catalysts and some basic structure-activity relations at the atomic scale, could facilitate the rational design of In_2O_3-based catalysts for MSR by controlling the local coordination environment of surface active sites.Indium oxide（In_2O_3） has demonstrated to be an effective non-noble metal catalyst for methanol steam reforming reaction（MSR）.However, the reaction mechanism of MSR and crucial structure-activity relations determining the catalytic performance of In_2O_3 are still not fully understood yet. Using density functional theory（DFT） calculation, we systematically investigate the MSR process over a high-index In_2O_3（211） and a favoured catalytic cycle of MSR is determined. The results show that In_2O_3（211） possesses excellent dehydrogenation and oxidizing ability, on which CH_3 OH can readily adsorb on the In4 c site and be easily activated by the reactive lattice oxygens, resulting in a total oxidation into CO_2 rather than CO, while the H_2 formation through surface H–H coupling limits the overall MSR activity because of the strong H adsorption on the two-coordinated lattice O（O_（2c））. Our analyses show that the relatively inert three-coordinated lattice O（O_（3c）） could play an important catalytic role. To uncover the influence of the local coordination of surface In atoms and lattice O on the catalytic activity, we evaluate the activity trend of several types of In_2O_3 surfaces including（211）,（111）, and（100） by examining the rate-limiting, which reveals the following activity order：（211）〉（111）〉（100）. These findings provide an in-depth understanding on the MSR reaction mechanism over In_2O_3 catalysts and some basic structure-activity relations at the atomic scale, could facilitate the rational design of In_2O_3-based catalysts for MSR by controlling the local coordination environment of surface active sites.

关 键 词：steam reforming reaction DFT In2O3 （211） reaction mechanism DEHYDROGENATION structure-activity relation 

分 类 号：O643.32[理学—物理化学]