Innovation synthesis of Zn0.5Cd0.5S/WO3 S-scheme heterostructures with significantly enhanced photocatalytic activity

Abstract

In our work, Zn0.5Cd0.5S/WO3 (ZCSW) S-scheme heterostructure composites were prepared by an innovation synthesis called electrostatic adsorption method, which supported to form high-quality hetero-interface connection to efficiently improve the photocatalytic activity. Specially, 1D Zn0.5Cd0.5S (ZCS) nanorods and 2D WO3 nanosheets were used to construct the S-scheme photocatalysts that have fully reflected both two components’ structural and morphological features. By DFT calculation, this S-scheme photogenerated electron transfer channel could be predicted by the work function between Zn0.5Cd0.5S (4.132 eV relative to vacuum level) and WO3 (5.175 eV), thus the practical effect of the S-scheme heterojunction could support the electron flow from the valence band of Zn0.5Cd0.5S to the conduction band of WO3 under the built-in electric field in the space charge region. Meanwhile, PL spectra and electrochemical measurement together reveal the photogenerated electron separation enhancement of ZCSW composites. For photocatalysis, ZCSW40 (40 stands for the weight ratio of WO3 versus Zn0.5Cd0.5S) was the best catalyst among the as-prepared samples with the Cr (VI) degradation rate of 20.4 μmol min−1·g−1cat., which was nearly 3 times and 2 times higher than those of bare ZCS and the rest of ZCSW photocatalysts under the simulated solar-driven irradiation. Furthermore, ZCSW40 possessed excellent cycling stability in photocatalytic reaction, as well as the highest reaction dynamic constant of 0.92103.