Coordination engineering of B/N-doped graphene with phosphorus-transition metal diatomic catalysts for enhanced oxygen bifunctionality electrocatalysis

Abstract

The design of highly active and cost-effective bifunctional catalysts for oxygen evolution (OER) and oxygen reduction (ORR) reactions is critical for advancing energy storage and conversion, yet significant challenges remain. Inspired by the efficient bifunctionality of graphene-based single-atom and diatomic catalysts in OER/ORR, we designed 42 structural of TMPX₄@graphene (X = B, N; TM = V-Pt) and A-B_N, and assessed their OER and ORR catalytic performance using density functional theory (DFT). The sum of overpotentials (η_sum = η_OER + η_ORR) was identified as an effective descriptor for predicting the bifunctional catalytic properties of the TMPX₄@graphene system. The transferred electron count and d-orbital occupation of Co atoms were identified as key sources of catalytic activity in OER and ORR, as determined through Bader charge analysis and partial density of states (PDOS). Finally, constant potential method (CPM) calculations showed that CoPB₄@graphene exhibits excellent catalytic activity under alkaline conditions, with ORR and OER overpotentials of 0.86 V and 1.38 V, respectively. This study highlights the importance of rationally designing the local coordination environment by regulating boron content to enhance catalytic activity. It further provides insights into the rational design of stable and efficient catalysts by considering electrode potential and pH effects in electrocatalytic systems.