Unique ternary Cd0.85Zn0.15S@WO3/WS2 core-shell nanorods for highly-efficient photocatalytic H2 evolution under visible-light irradiation

Abstract

Development of noble-metal-free photocatalysts for efficient solar-powered water-splitting is of great interest yet still challenging to date. In this work, unique ternary Cd0.85Zn0.15S@WO3/WS2 (CZ0.15S@WO3/WS2) core-shell nanorods consisting of amorphous WO3 and few-layered WS2 nanosheets were synthesized through a two-step solvothermal method for the first time. The composition of WO3/WS2 shell is found to vary with the change of W content, which has a significant impact on the photocatalytic property of CZ0.15S@WO3/WS2 toward H2 evolution reaction (HER). Under visible-light irradiation (λ > 420 nm), the optimized CZ0.15S@WO3/WS2 composite (n (WO3): n (WS2) = 3:1) demonstrates a superior HER activity of 76.33 mmol h−1 g−1 (corresponding to an AQY of 23.9% at 420 nm), which can be further remarkably increased to 157.29 mmol h−1 g−1 when the reaction is driven by full Xe-lamp spectrum. The HER capability of CZ0.15S@WO3/WS2 is much better than that of Pt-decorated CZ0.15S and most CdS-based photocatalysts ever reported, due to the notably enhanced charge transfer and separation via the synergistic cooperation of Z-scheme and type-I charge transfer processes. The findings displayed here could inspire new strategies to optimize the charge separation of multi-component photocatalysts for highly-effective solar conversion and utilization.