A 1T-WS2 “electron pump” regulates charge transfer over ZnCdS/NiV-LDH p–n heterostructures for enhanced photocatalytic hydrogen evolution

Abstract

Dynamics and morphology play a crucial role in the field of photocatalytic hydrogen production. Regulating the transfer of photogenerated charges is an effective way to improve the catalytic activity. In this paper, 1T-WS₂ is introduced into a p–n heterostructure, ZnCdS/NiV-LDH, as a metalloid electron pump to transfer photogenerated electrons from semiconductors with larger work functions to metalloid materials with smaller work functions, effectively to attract photogenerated electrons, and promote charge rearrangement at the p–n heterostructure interface, so as to achieve the best utilization efficiency of photogenerated charges. Second, adjusting the morphology to increase the light absorption area of the catalyst is also a way to improve the photocatalytic activity. Two different nanosheet structures dispersed heavily stacked ZnCdS, increasing the light absorption area of the system. The optimal catalyst ratio achieves a hydrogen evolution rate of 22.37 mmol g⁻¹ h⁻¹, achieving 7.98% AQE and 2.12% STH conversion efficiency at 450 nm. The potential mechanism was demonstrated through in situ XPS. This study provides new insights into adding “electron pumps” to heterostructures to enhance photocatalytic activity.