First-principles study of electronic, optical, and photocatalytic water-splitting properties in two-dimensional BP/Mo₂C Schottky heterojunction

Abstract Schottky heterojunctions are recognized as efficient photocatalysts due to their high carrier mobility and effective separation of photogenerated electron–hole pairs. Through first-principles calculations, the BP/Mo 2 C Schottky heterojunction demonstrates both high carrier mobility and structural stability. The photocatalytic mechanism was elucidated through analysis of photogenerated carrier transition pathways using the principles of built-in electric field and band bending theory. Remarkably, the BP/Mo 2 C Schottky heterojunction displays superior light absorption across visible and ultraviolet spectra, achieving an exceptional Solar-To-Hydrogen (STH) conversion efficiency of 45.08%. Free energy calculations confirm spontaneous hydrogen evolution reaction (HER) activity at the BP/Mo 2 C Schottky heterojunction, with oxygen evolution reaction (OER) also proceeding spontaneously under neutral conditions. These collective properties establish the BP/Mo 2 C Schottky heterojunction as a highly efficient photocatalyst for comprehensive water splitting.