Theoretical study of Mo2N supported transition metal single-atom catalyst for OER/ORR bifunctional electrocatalysis.

Abstract

The rational design and development of an efficient bifunctional catalyst for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is the key to developing new renewable energy storage and conversion technologies. Transition metal nitrides (TMNs) have shown excellent energy storage and electrochemistry potential due to their unique electronic structure and physicochemical properties. In this paper, based on the first-principles method of density functional theory (DFT), a series of efficient and stable bifunctional single-atom catalysts (SACs) were designed on Mo2N by introducing transition metal atoms as active sites, and the effects of different TM atoms on the catalytic performance of 2D-Mo2N (Two dimensional Mo2N) were evaluated. The calculation results show that TM@Mo2N exhibits excellent stability and good conductivity, which is conducive to electron transfer during the electrocatalytic reaction. Among these SACs, the Au@Mo2N single-atom catalyst has a very low OER overpotential (0.36 V), exhibiting high OER activity. Meanwhile, Au@Mo2N also exhibits excellent ORR performance with a low overpotential of 0.4 V, indicating that Au@Mo2N is the best OER/ORR bifunctional catalyst. This work provides a feasible solution for developing transition metal bifunctional electrocatalysts. Au@Mo2N is expected to replace traditional commercial Pt catalyst materials and become a catalyst with excellent performance in fuel cell modules.