采用密度泛函理论研究了氢气在镍掺杂的镁(0001)面上的解离吸附过程.通过固定键长法计算得到氢分子在镍掺杂的镁(0001)面上的解离能垒为0.09eV,而在清洁镁(0001)面上,氢气的解离能垒为1.15eV.电子结构分析表明,解离能垒的降低是由于氢分子与表面镍原子形成反馈键并被填充所致.这一计算结果表明,在镁中加入过渡金属催化剂会大大提高储氢材料的动力学性能.
Hydrogen dissociation on Ni-doped Mg(0001) surface was studied by density functional theory calculations. Using the fixed-bond method, a dissociation barrier of 0.09 eV was obtained in contrast to 1.15 eV on a clean Mg(0001) surface reported in the literature. Electronic structure analysis shows that the decrease of the dissociation barrier comes from filling of the σ^* orbital due to the back donation through the doped Ni atom. The results indicate that the kinetics of hydrogen uptake is dramatically enhanced by doping transition metal catalysts.