Ternary rGO decorated W₁₈O₄₉ @g-C₃N₄ composite as a full-spectrum-responded Z-scheme photocatalyst for efficient photocatalytic H₂O₂ production and water disinfection

Integrating g-C3N4 with narrow-band semiconductor to construct a Z-scheme structured heterojunction has been regarded as a common strategy to improve the photocatalytic performance of g-C3N4. However, limited catalytic activity increment is achieved due to the contradiction of expanding the light absorption scope of traditional photo-oxidation semiconductors (PS II) and preserving their valance band oxidative abilities. Herein, to extend the light absorption range of g-C3N4 based Z-scheme photocatalyst to the whole solar spectra while without losing the high oxidative ability of this system, we select the heavy doped W18O49 as PS II and provide a facile in situ hydrothermal method to elaborately fabricate an rGO decorated W18O49 @g-C3N4 (r-CNW) Z-scheme photocatalyst. The prepared r-CNW-2 (with optimal W18O49 to g-C3N4 weight ratio of 1:2) exhibits improved photocatalytic performance with H2O2 generation rates of 71, 58.5 and 6.3 mu mol g(-1) h(-1) obtained under the simulated solar light, visible light (>400 nm) and NIR light (>800 nm) irradiation, respectively, which is 1.3 and 2 times higher than those of the g-C3N4 counterparts (54, 29 mu mol g(-1) h(-1) and even not detected).such outstanding performance of r-CNW-2 could be associated with the broader light absorption, fast charge separation, and rapid redox reactions. Moreover, the r-CNW-2 also displays an excellent E-coli inactivation activity, comparable to most g-C3N4-based photocatalysts. Our work gives a new insight through trading off light absorption and redox ability to fabricate efficient Z-scheme photocatalyst for photocatalytic H2O2 generation and environmental remediation.