Ag supported Z-scheme WO2.9/g-C3N4 composite photocatalyst for photocatalytic degradation under visible light

Abstract

Efficient utilization of photo-induced carriers and adsorption capacity is a promising approach to realize positive photocatalytic dye degradation. Yet the ability to reliably combine both features within one photocatalytic system, especially inorganic stuff is challenging. Here we reported the formation of WO2.9 with oxygen vacancy demonstrating better adsorption capacity promotion in comparison with traditional WO3. Besides, resorting to Ag nanoparticles as cocatalyst supported WO2.9 on g-C3N4 (Ag/WO2.9/g-C3N4) catalyst has been constructed, which has low-energy of electrons in WO2.9 neutralized with holes in g-C3N4, leaving intensive energy holes from WO2.9 for hydroxyl radical generation and electrons of g-C3N4 resulted in superoxide radical. Depending on the dual radicals existence and exploited adsorption capacity promotion, Ag/WO2.9/g-C3N4 exhibited desired photo-degradation performance for Rhodamine B, methylene blue and methyl orange under visible light irradiation (λ ˃ 420 nm), which was distinctly better than single Ag/WO2.9 and onefold g-C3N4. In the end, a possible Z-scheme photocatalytic mechanism was proposed to explain the effective separation of photogenerated carriers Ag/WO2.9/g-C3N4 heterojunctions. This work expanded our understanding between structure-property and photocatalytic activity and applied this understanding to design highly photoactive catalyst.