Molybdenum nitride for the direct decomposition of NO

Abstract

The physico-chemical properties of passivated γ-Mo₂N have been investigated. The material showed high activities for NO direct decomposition: nearly 100% NO conversion and 95% N₂ selectivity were achieved at 450 ^○C. The amount of O₂ taken up by γ-Mo₂N increased with temperature rise and reached 3133.9 μmol g⁻¹ at 450 ^○C; we conclude that there formation of Mo₂O_xN_y occurred. This oxygen-saturated γ-Mo₂N material was catalytically active: NO conversion and N₂ selectivity were 89 and 92% at 450 ^○C. We found that by means of H₂ reduction at 450 ^○C, Mo₂O_xN_y could be reduced back to γ-Mo₂N and the oxidation/reduction cycle is repeatable; such a behaviour and the high oxygen capacity (3133.9 μmol g⁻¹) of γ-Mo₂N suggest that γ-Mo₂N is a promising catalytic material for automobile exhaust purification.