Chemically anchoring molybdenum atoms onto micropore-rich VN nanosheet for boosted nitrogen electro-fixation via hydrogen bonds

Abstract

The hydrogenation of N2 is critical for nitrogen reduction reaction (NRR) and heavily relies on weak van der Waals forces, which leads to sluggish N2 activation. Herein, we put forward a hydrogen-bonding (H-bonding) strategy to promote N2 hydrogenation via chemically anchoring tetrahedron molybdate ([MoO4]) moieties onto micropore-rich VN nanosheets (Mo-VN). In Mo-VN, monodispersed Mo atoms linked with three equivalent end-on oxygen atoms anchor in VN matrix through bridging oxygen with O─Mo─O─V─N configurations, which strongly drive the proton-hydrogen migrate to the adsorbed N2 by H-bonding with NN-H···O-Mo formation, facilitating N2 adsorption and activation. The obtained Mo-VN catalysts deliver an excellent and stable catalytic performance for NH3 production, surpassing most N-containing catalysts. Experimental and theoretical calculations results confirm that the O─Mo─O─V─N bonding environment accelerates all hydrogenation steps of N2 and enables efficient nitrogen activation, which efficiently promote the intrinsic NRR activity and stability. This work opens up a new avenue for developing high-efficiency catalysts through H-bonding strategy.