中文摘要：

采用密度泛函理论,在电子水平上研究了NiMn双金属与MgO载体间的相互作用以及这种相互作用对H原子吸附和H_2解离的影响,并把所得结果与Ni/MgO上相应的结果作比较。研究过程中分别采用完美的和有缺陷的MgO载体负载Ni_2Mn_2簇,构建了两种催化剂模型。结果表明,表面有缺陷的MgO与活性组分Ni_2Mn_2间的相互作用大于完美面MgO与活性组分间的相互作用,H原子在有缺陷的MgO负载的Ni_2Mn_2催化剂上的吸附能大于完美面MgO负载的Ni_2Mn_2催化剂上的吸附能,并且有缺陷的MgO负载的Ni_2Mn_2催化剂更有利于H_2解离;与Ni4负载的MgO上金属与载体间相互作用相比较,添加第二种金属Mn会使活性组分与MgO载体间的相互作用减弱,吸附H原子的能力增强,但是不利于H_2解离。此结果为通过加入第二种金属或改变载体来调变金属-载体间相互作用进而改变催化剂性能的实验研究提供了理论线索。

英文摘要：

Density functional theory has been employed to investigate the interaction between NiMn bimetal and MgO support,further to investigate the influence of the interaction on H adsorption and H_2 dissociation,and the results were compared with those on Ni/MgO.Two catalyst models,i.e.,perfect and defective MgO supported Ni_2Mn_2 clusters were built to represent the modeling catalyst.The results show that the interaction of defective MgO and active component Ni_2Mn_2 is stronger than that between perfect MgO and active component Ni_2Mn_2,and the adsorption of H on defective Ni_2Mn_2/MgO is stronger than that on perfective one,and further,H_2 dissociation is favorable on defective Ni_2Mn_2/MgO compared that on perfect Ni_2Mn_2/MgO.Compared to MgO supported Ni_4,the addition of a second metal Mn makes the interaction between active component and MgO support decrease,correspondingly,the ability of H adsorption is increased while the ability of H_2 dissociation is reduced.This study provides the theoretical clue for experimental preparation to modify the interaction of metal and support through addition a second metal,further to tune the catalyst performance.