Structural, Electronic and Photocatalytic Properties of P-Doped g-C3N4: A DFT Analysis

Solar-driven photocatalytic water splitting is a promising approach for green hydrogen production. Despite the great potential of g-C3N4 photocatalysts, non-metal doping studies currently suffer from conflicting results and unclear doping configurations. Herein, first-principles calculations were adopted to compare P-, O-, and S-doped g-C3N4. P-g-C3N4 with P substituting N shows the best stability, a narrower band gap, and enhanced visible light absorption. It achieves high carrier mobility and suitable band edges for overall water splitting, with a maximum STH efficiency of 15.8%. This work clarifies doping mechanisms and offers solid theoretical support for developing high-performance g-C3N4-based photocatalysts.