The density functional theory (DFT) method has been used to reveal the underlying mechanism of Ni cluster supported on ZrO2 (111) as well as the activity and selectivity of CO methanation.CO→HCO→CH2 O→CH2→CH3→CH4 is mainly responsible for CH4 formation on Ni4-ZrO2 (111),while CH4 is mainly formed via the path of CO→HCO→CH→CH2→CH3→CH4 on Ni13-ZrO2 (111).Ni4-ZrO2 (111) and Ni13-ZrO2 (111) exhibit similar activity for CH4 formation with the free energy barrier of 2.38 eV and 2.26 eV,respectivley.In addition,Ni13-ZrO2 (111) displays a remarkable high selectivity to CH4 comparing with Ni4-ZrO2 (111).Moreover,Ni4-ZrO2(111) exhibits high resistance to carbons,while Ni13-ZrO2 (111) surface is much sensitively to form deposition carbon.%采用量子化学密度泛函理论(DFT)研究了负载型催化剂Ni/ZrO2(111)的CO甲烷化活性和选择性.结果表明:CO→CHO→CH2O→CH2→CH3→CH4是Ni4-ZrO2(111)面上CH4形成的有利路径,CO→HCO→CH→CH2→CH3→CH4是Ni13-ZrO2(111)面上CH4形成的有利路径,这两种催化剂具有相似的CH4生成活性,Ni13-ZrO2(111)比Ni4-ZrO2(111)具有明显高的CH4选择性.Ni4·ZrO2(111)能较好地抑制积碳.
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