XPS has been applied to study the reduction influence of the passivated Mo2N sample on H2 chemisorption at room temperature. It is found that most of the Mo6+ species was reduced to low valence molybdenum species (Moδ+:δ■4) when reduc tion temperature was raised up to 673K, meanwhile sharp increases of both the irreversible and reversible hydrogen uptakes were measured. The irreversible amount increased to a larger extent. Accordingly, the active sites towards hydrogen adsorption are tentatively proposed to the low valence molybdenum species with nitrogen deficient. XPS has been applied to study the reduction influence of the passivated Mo2N sample on H2 chemisorption at room temperature. It is found that most of the Mo6 + species was reduced to low valence molybdenum species (Moδ +: δ ■ 4) when reduc tion temperature was The irreversible amount increased to 6 larger, boldly of both increases irreversible and increased reversible hydrogen uptakes were measured. The irreversible amount increased to a larger extent.