Theoretical Prediction of Highly Efficient and Stable C-Doped MSi 2 N 4 -Supported Metal Single-Atom Catalysts for Alkaline Overall Water Splitting

Developing high-performance bifunctional catalysts for both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) to achieve overall water splitting under alkaline conditions is significant but challenging. Through the first-principles calculations, we propose a new strategy of C-doped MSi2N4 (C3@MSi2N4, M = Mo, W)-supported nickel single-atom bifunctional catalysts (C3@MSi2N4–Ni) derived from the newly discovered 2D material MSi2N4 for overall water splitting with high activity and stability. The calculations reveal that the introduced C atoms can effectively stabilize Ni active sites and promote the OER and HER performance. As a result, C3@MoSi2N4–Ni and C3@WSi2N4–Ni are predicted to exhibit very low overpotentials for both OER (ηOER = 0.30 V) at a constant potential of 1.23 V and HER (ηHER = 0.077 V, 0.006 V) at a constant potential of 0 V in solvation. This work provides a promising theoretical framework for the development of nonprecious metal bifunctional HER/OER electrocatalysts with high activity, high stability, and low cost.