All-solid-state Z-scheme nanojunction PW12/Ag/ZnO photocatalyst: Effective carriers transfer promotion and enhanced visible light driven

Abstract

By coupling two semiconductors with favorable band gap, ZnO (PS I) and Keggin-type tungstophosphate (PW12, PS II), an interesting all-solid-state Z-scheme photocatalyst PW12/Ag/ZnO has been designed and synthesized. In the developed composite PW12/Ag/ZnO, noble metal silver nanoparticle as an efficient conductor constructs an efficient spatial charge separation and carriers transfer process. By controlling reaction conditions, the UV–Vis absorption of Ag nanoparticles in the designed all-solid-state Z-scheme complex is gradually improved from about 400 nm to near infrared region. Benefited from its effective visible light absorption, the developed photocatlyst exhibits favorable UV-visible response, enhanced photocatalytic performance with optimum photodegradation of PW12/Ag-4/ZnO-6 for model dye (RhB ca. 99.93% at pH=6) and high reaction kinetics. Results show that the migration pathway of the charge carriers in this ternary system is significantly altered in counterparts of binary catalysts PW12/Ag and PW12/ZnO. The synergy catalysis interaction occurs between ·OH and ·O2− during the photodegradation process of PW12/Ag/ZnO composites. This work offers insights into the construction of efficient and stable all-solid-state Z-scheme heterostructures based on POMs.