Metallic WO2-decorated g-C3N4 nanosheets as noble-metal-free photocatalysts for efficient photocatalysis

The introduction of a metallic cocatalyst is a good strategy for achieving a high carrier density and absorbing photons under wide-spectrum illumination. Herein, metallic WO2/g-C3N4 nanocomposites were designed and synthesized for the first time using a simple calcination method to enhance the photocatalytic performance. WO2/g-C3N4 exhibited significant photocatalytic properties: under visible light irradiation, 4 wt% WO2/g-C3N4 exhibited an RhB photocatalytic degradation of 96% in 120 min. Meanwhile, the H2 production rate of 4 wt% WO2/g-C3N4/3 wt% Pt was 2436.9 μmol g−1 h−1, which was 2.55 and 6.18 times higher than that of 3 wt% Pt/g-C3N4 (956.35 μmol g−1 h−1) and WO2/g-C3N4, respectively. Experimental tests and density functional theory calculations reveal that WO2 exhibits a metal-like performance with a narrow bandgap to capture electrons and hinders the recombination of photogenerated charge carriers at the interface of WO2/g-C3N4. Our study provides a new perspective for the rational design of metallic cocatalysts/semiconductors with highly efficient photocatalytic properties.