Fabrication of hierarchical sheet-on-sheet WO3/g-C3N4 composites with enhanced photocatalytic activity.

Abstract Novel hierarchical sheet-on-sheet WO 3 /g-C 3 N 4 (WOCN) composites were successfully fabricated by simple calcination method using acid-treated SrWO 4 /g-C 3 N 4 as precursors. The morphological observation showed that WO 3 nanosheets were closely anchored on the surface of g-C 3 N 4 nanosheets to construct a hierarchical nanostructure. The as-synthesized WOCN composites exhibited a significantly higher photocatalytic activity towards the photocatalytic degradation of rhodamine B (RhB) compared to pristine g-C 3 N 4 and WO 3 under simulated sunlight irradiation. The optimum photocatalytic activity of the WOCN at a WO 3 mass content of 34.6% was 6.5 and 3.0 times higher than that of pristine WO 3 and g-C 3 N 4 , respectively. The enhanced photocatalytic activities of WOCN composites were attributed to the formation of hierarchical heterostructure, which provided larger specific surface area, better visible-light absorption capability, reduced the recombination of photogenerated electron-hole pairs and enhanced separation efficiency of charge carriers. A Z-scheme photocatalytic mechanism was proposed according to active species trapping experiments. Graphical abstract Image 1 Highlights • Hierarchical sheet-on-sheet WO 3 /g-C 3 N 4 composites were successfully synthesized. • The composites provided larger surface area than pristine g-C 3 N 4 and WO 3. • The hierarchical heterostructure facilitated charge separation and transfer. • The composites exhibited enhanced photocatalytic activity and high stability. • A Z-scheme photocatalytic mechanism was proposed. [ABSTRACT FROM AUTHOR]