Rationally constructing of a novel dual Z-scheme composite photocatalyst with significantly enhanced performance for neonicotinoid degradation under visible light irradiation

A novel dual Z-scheme g-C3N4/WO3/AgI photocatalyst was rationally constructed via a two-step method (electrostatic self-assembly plus selective deposition). Firstly, binary g-C3N4/WO3 system was fabricated by electrostatic self-assembly method. Then, Ag ions were selectively adsorbed on the surface of negatively charged WO3 and reacted with I ions to form AgI nanoparticles. Compared with pure g-C3N4, WO3, AgI and their binary composites, the ternary composites showed significantly enhanced photocatalytic performance for nitenpyram (NTP) degradation under visible light. The enhanced performance can be ascribed to the increased charge transferring/separation efficiency and remaining high reduction/oxidation ability of the photo-generated electrons/holes in the dual Z-scheme system. Furthermore, the possible degradation pathway of NTP was deduced based on the results of high-performance liquid chromatography mass spectrometry (HPLC-MS). This work would broaden insight into the rationally construction of highly efficient Z-scheme composite photocatalysts.