Single Metal Atom Supported on N-Doped 2D Nitride Black Phosphorus: An Efficient Electrocatalyst for the Oxygen Evolution and Oxygen Reduction Reactions

Studies on the application of two-dimensional black phosphorus (BP) nanocrystals in electrocatalysis have been paid much attention. In this work, we designed a single-atom catalyst (SAC) in which transition-metal atoms were supported on the N-doped BP (denoted as MNx–BP, M = Fe, Co, Ni; x = 0–3) and systematically studied their catalytic performance for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) in alkaline conditions by means of density functional theory (DFT) calculations. The DFT calculation results indicated that the catalytic activity of MNx–BP is significantly affected by the number of doped N atoms surrounding the single-metal center. The coordination of N atoms adjusts the adsorption strength of oxygenated intermediates over the metal center, thus affecting the catalytic performance of MNx–BP. In particular, the SAC of CoN3–BP exhibited the highest activity for OER (the overpotential η value was 0.48 V for the OER), while NiN3–BP has the highest activity for ORR (the overpotential η value was 0.44 V for the ORR). This work provided a new perspective on the design of a single-atom catalyst loaded on BP for the OER and ORR processes.