H2在Mg(0001)和M(Sc～Zn)/Mg(0001)表面吸附、脱附性能研究

采用密度泛函方法,对H2在Mg(0001)及掺杂一系列的过渡金属的Mg表面的吸附行为进行了研究.结果表明,H2在Mg(0001),Fe,Co,Cu和Zn掺杂的Mg表面只存在物理吸附；在Sc,Ti,V,Cr,Mn和Ni掺杂的Mg表面时物理吸附和化学吸附都存在.H2在M(Sc～Zn)掺杂Mg表面解离的能垒均低于Mg(0001)表面.解离后的H原子易化学吸附在以下3种邻近的空位:Fe掺杂Mg表面的fcc-hcp1位;Ni掺杂Mg表面的hcp-hcp位；其余掺杂Mg表面的fcc-fcc位.计算结果显示,Ti,V,Cr,Mn,Ni掺杂在Mg表面可有效改善H2的吸附与解离性能.

Theoretical Study of Adsorption and Desorption Properties of Hydrogen on Mg(0001) and M (Sc-Zn)-Doped Mg(0001) Surfaces

Hydrogen adsorption and desorption properties on clean and M(Sc-Zn) doped Mg(0001) surfaces are investigated systematically by the density functional theoretical method.The results show that H2 is adsorbed physically on Mg(0001),Fe-,Co-,Cu-and Zn-doped Mg surfaces,but can be adsorbed both physically and chemically on Sc-,Ti-,V-,Cr-,Mn-and Ni-doped Mg surfaces.The energy barrier for hydrogen dissociation on the pure Mg(0001) surface is the highest compared with those on M-doped surfaces.The dissociated hydrogen atoms are apt to be adsorbed chemically in the following three kinds of neighboring sites: fcc-hcp1 sites of Fe-doped Mg,hcp-hcp sites of Ni-doped Mg and fcc-fcc sites of the other kinds of M-doped Mg.The above calculation results demonstrate that Ti,V,Cr,Mn and Ni are appropriate candidate doping metals for improving the adsorption and dissociation properties of H2.