Single Metal Atoms Anchored on Defective Phosphorus Carbide as a Stable and High-Performance Electrocatalyst for Nitrogen Reduction

Abstract

The electrochemical nitrogen reduction reaction (NRR) is a promising alternative to the traditional Haber-Bosch process, which can directly convert N2 into NH3 powered by renewable electricity. However, it remains a challenge to synthesize stable NRR catalysts with high catalytic activity and selectivity for practical applications. Herein, we systematically investigate a series of metal atoms (V–Ni, Nb–Mo, and Ta–W) anchored on two-dimensional (2D) phosphorus carbide with C vacancy (M@VC) and P vacancy (M@VP) as a potential electrocatalysts for NRR. We demonstrate that W@VP has high kinetic and thermodynamic stability, exhibiting superior catalytic activity toward NRR with a low limiting potential of −0.50 V vs RHE and excellent NRR selectivity. The physical origin is attributed to the localized spin density on the W atom, as well as the hybridization between 2π* orbitals of N2 and d orbitals of W. Importantly, we demonstrate a linear relationship between catalytic activity and the adsorption energy of the N2H intermediate, a great benefit for future screening of NRR catalysts. Our results provide valuable guidance for designing stable and high-efficiency single-atom catalysts based on 2D structures.