中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 19 No. 2 April 2009 |
（1. Shanghai Key Laboratory of Modern Metallurgy and Materials Processing, Shanghai University,
Shanghai 200072, China;
2. Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083, China;
3. College of Science, Shanghai University, Shanghai 200444, China）
Abstract: A small amount of Fe3O4 catalyst is known to substantially improve the adsorption and desorption thermodynamics and kinetics of Mg-based materials. Using density functional theory in combination with nudged elastic band method, the dissociative chemisorptions of hydrogen on both pure and Fe-doped Mg(0001) surfaces were studied. The adsorption energy calculations show that a weakly physisorbed state above pure and Fe-doped Mg surface atoms can serve as a precursor state to dissociative chemisorption. Then, the dissociation pathway of H2 and the relative barrier were investigated. The calculated dissociation barrier (1.08 eV) of hydrogen molecule on a pure Mg(0001) surface is in good agreement with comparable experimental and theoretical studies. For the Fe-doped Mg(0001) surface, the activated barrier decreases to 0.101 eV due to the strong interaction between the s orbital of H and the d orbital of Fe.
Key words: magnesium alloy; hydrogenation mechanism; catalyst effect; density functional theory
