CdS nanodots adorned (020)-featured WO3·H2O nanoplates heterojunction with augmented photocatalytic hydrogen production under Z-scheme charge transfer mechanism

In this paper, controllable nucleation and growth of CdS nanodots on the (020)-featured WO 3 ·H 2 O nanoplates has been successfully accomplished to prepare CdS-WO 3 ·H 2 O heterojunction with high-quality interfacial contact through a slow release of Cd 2+ and S 2- from the gradual self-loop hydrolysis of cadmium acetate and thioacetamide. The chemical and structural characteristics of as-prepared samples before and after heat treatment are detailedly investigated by TG-DSC, XRD, Raman, XPS, FESEM and HRTEM, as well as their light absorption performance from UV-Vis DRS. The maximum average hydrogen production rate for CdS-WO 3 ·H 2 O reaches 2.15 mmol·g −1 ·h −1 under 300 W Xe lamp irradiation (λ > 420 nm) using lactic acid as sacrificial reagent, which is 8.27 and 2.72 times as much as CdS and CdS-WO 3 , respectively. According to band alignment, CdS-WO 3 ·H 2 O exhibits greater energy difference of Fermi level than CdS-WO 3 , and augmented photocatalytic performance should arise from efficient Z-scheme charge transfer mechanism under stronger built-in electric field, in which the conduction band electrons of WO 3 ·H 2 O and valence band holes of CdS are expected to effectively recombine at their interfacial zones, while the conduction band electrons of CdS and valence band holes of WO 3 ·H 2 O contribute to the reduction of H + and oxidation of lactic acid.