Conversion of NO into N2 over γ-Mo2N

Abstract

Cubic molybdenum nitride (γ-Mo2N) exhibits Pt-like catalytic behavior in many chemical applications, most notably as a potent catalyst for conversion of harmful NOx gases into N2. Guided by experimental profiles from adsorption of 15NO on γ-Mo214N, we map out plausible mechanisms for the formation of the three isotopologues of dinitrogen (14N2, 15N2, and 14N15N) in addition to 14N15NO. By deploying cluster models for the γ-Mo2N(100) and γ-Mo2N(111) surfaces, we demonstrate facile dissociative adsorption of NO on γ-Mo2N surfaces. Surfaces of γ-Mo2N clearly activate adsorbed 15NO molecules, as evidenced by high binding energies and the noticeable elongation of the N–O bonds. 15NO molecule dissociates through modest reaction barriers of 24.1 and 28.1 kcal/mol over γ-Mo2N(100) and γ-Mo2N(111) clusters; respectively. Dissociative adsorption of a second 15NO molecule produces the experimentally observed Mo2OxNy phase. Over the 100 surface, subsequent uptake of 15NO continues to occur until the dissociated O and...