Rational design of 2D MBene-based bifunctional OER/ORR dual-metal atom catalysts: a DFT study.

Designing highly active, low-cost, and bifunctional oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) catalysts is urgent for the development of metal-air batteries. Herein, by density functional theory (DFT) calculations, we systematically reported a series of dual-metal atom adsorbed novel two-dimensional (2D) MBenes as efficient bifunctional catalysts for the OER/ORR (namely 2TM/TMTM-MoBO, TM = Mn, Fe, Co, Ni). Our theoretical results show that 2Ni-MoBO, FeCo-MoBO and CoNi-MoBO exhibit outstanding OER/ORR catalytic activity with overpotentials of 0.49/0.27 V, 0.38/0.50 V and 0.25/0.51 V, respectively, exceeding those of IrO(110) for the OER and Pt(111) for the ORR. Additionally, these highly active bifunctional catalysts can effectively suppress the hydrogen evolution reaction (HER), ensuring the absolute preference for the OER/ORR. More importantly, the Bader charge () of adsorbed dual-metal atoms is used as a descriptor of OER/ORR catalytic activity, which is linearly related to and volcanically related to -. Our work not only provides new theoretical guidance for developing noble metal-free bifunctional electrocatalysts but also enriches the application of MBenes in electrocatalysis.