Adsorption and migration of hydrogen on different surface sites of γ-Mo2N catalyst

Abstract

Temperature programmed desorption (TPD) and temperature programmed adsorption (TPA) techniques were applied to study the mobility and migration of hydrogen species on high surface area Mo nitride catalyst. It was found that there are two kinds of adsorption site on γ-Mo2N one with low adsorption energy and the other with high adsorption energy respectively, and the catalyst shows a higher adsorption capacity at higher adsorption temperatures. TPD and TPA results revealed that hydrogen adsorption-desorption on γ-Mo2N depends strongly on temperature. The adsorbed hydrogen species exhibits such high mobility that hydrogen species migrate from sites with low adsorption energy to sites with high adsorption energy. The TPD results show that the hydrogen species can migrate between different surface states to maintain a dynamic equilibrium.