Doping induced asymmetry adjacent structure in h-VN nanoribbon for the promotion of N2 fixation

Abstract

Vanadium nitride (VN)-based materials have attracted increasing attention in the field of electrochemical catalysis due to their unique structure and inherent electronic properties. However, the nitrogen reduction reaction (NRR) performances of such nitrogen-containing catalysts render very low catalytic activities, and it is a challenge to achieve optimal efficiency. In this work, we propose a strategy for doping hetero-metal atoms to promote nitrogen fixation on vanadium nitrides by using density functional theory (DFT) calculations. We evaluated and compared the activity and selectivity of NRR on in-plane sites as well as on edge sites. We found that the first half of the elements showed high doping rates. Moreover, the NRR catalytic performance of VN can be boosted by a specific metal atom doping strategy, which significantly promotes the N2 adsorption as well as both the activity and selectivity. Finally, the heterogeneous atom pair (HTAP) VMo@edge and VTi@in-plane/edge were selected as the most potential candidates that exhibit the rate-determining step as low as ∼0.2 and ∼0.6 eV, respectively. Our work provides not only a fundamental understanding of the NRR mechanism on VN-based materials, but also a powerful strategy for designing efficient bimetallic NRR electrocatalysts.