The Theoretical Research On Small Organic Adsorbed On Noble Metal Supported MgO (001) Surface

Due to single atom precious metals catalysts have attracted wide attention in oxidation,dehydrogenation and hydrogenation reduction.The theory investigation on the adsorption and decomposition of small organic molecular supported MgO(001)is favor in understanding electronic structure,bonding mechanism and reaction path and so on,and provided a certain theoretical basis for synthesing a type of catalyst,which has important significance on industry and scientific research.Using density functional theory combine with intermolecular forces,we have systematic research the adsorption and dissociation of CH3OH,HCHO and CH3NH2 organic small molecules in the precious metal atom supported MgO(001)surface.The results show that:1.Noble metal single atom M(Ni,Pd,Pt)tend to adsorb on O_top site of MgO(001)surface.For Ni1/MgO(001)surface,there are two adsorption structures,namely ?1(O)and?2(C,O)configurations,and the latter adsorption energy is higher than the former.But for Pd1/MgO(001)and Pti/MgO(001)surface,there is only one ?2(C,O)adsorption configuration.The adsorption energies on three different surfaces follow an order of Pti/MgO(001)>Nii/MgO(001)>Pd1/MgO(001).The charge transfers from metal-oxidation surface to small molecules,which increases the bond length of C-O and C-H.2.CH3OH through O atom combines with top site on pure MgO(001)and Pd1/MgO(001)surface.And the adsorption energies value of the latter is greater than the former.For CH3OH,the three pathways are investigated,such as the initial C-O scission,O-H and C-H scission.Finally,the results show that the path 2(CH3OH?CH3O?CH2O?CHO?CO+H)is the most possible decomposition path.3.CH3NH2 through N atom interactes with Pd top and Pt top site of Pd1/MgO(001)and Pt1/MgO(001)surface.And the activation energy barrier on Pt1/MgO(001)is lower than Pd1/MgO(001)surface,CH3NH decomposition pathways is investigated through N-H and C-H scission on Pt1/MgO(001)surface,the results show that the most possible decompostion pathway is CH3NH2?CH3NH?CH3N?CH2NH?CH2N?HCN,and the hydrogen ion from CH3NH species to CH3N is the rate-determining steps for all the dissociation reaction.