DFT研究负载于ZrO_2(111)上Ni簇的CO甲烷化:微粒尺寸的影响（英文）

Insight into the Effect of Particle Sizes for Ni Clusters Supported on ZrO_2(111) During CO Methanation:A DFT Study

采用量子化学密度泛函理论(DFT)研究了负载型催化剂Ni/ZrO_2(111)的CO甲烷化活性和选择性.结果表明:CO→CHO→CH_2O→CH_2→CH_3→CH_4是Ni_4-ZrO_2(111)面上CH_4形成的有利路径,CO→HCO→CH→CH_2→CH_3→CH_4是Ni_(13)-ZrO_2(111)面上CH_4形成的有利路径,这两种催化剂具有相似的CH_4生成活性,Ni_(13)-ZrO_2(111)比Ni_4-ZrO_2(111)具有明显高的CH_4选择性.Ni_4·ZrO_2(111)能较好地抑制积碳.

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→CH2O→CH2→CH3→CH4is 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.