Enhanced Photocatalytic CO(2) Reduction in Defect-Engineered Z-Scheme WO(3–x)/g-C(3)N(4) Heterostructures

[Image: see text] Oxygen vacancy-modified WO(3–x) nanorods composited with g-C(3)N(4) have been synthesized via the chemisorption method. The crystalline structure, morphology, composition, band structure, and charge separation mechanism for WO(3–x)/g-C(3)N(4) heterostructures are studied in detail. The g-C(3)N(4) nanosheets are attached on the surface of WO(3–x) nanorods. The Z-scheme separation is confirmed by the analysis of generated hydroxyl radicals. The electrons in the lowest unoccupied molecular orbital of g-C(3)N(4) and the holes in the valence band of WO(3) can participate in the photocatalytic reaction to reduce CO(2) into CO. New energy levels of oxygen vacancies are formed in the band gap of WO(3), further extending the visible-light response, separating the charge carriers in Z-scheme and prolonging the lifetime of electrons. Therefore, the WO(3–x)/g-C(3)N(4) heterostructures exhibit much higher photocatalytic activity than the pristine g-C(3)N(4).