Promoted Interfacial Charge Transport and Separation of Size-Uniform Zn, Ni-Doped CdS-1T/2H O-MoS₂ Nanoassemblies for Efficient Visible-Light Photocatalytic Water Splitting

Abstract

Producing solar fuels by photocatalysis has been of great interest in recent years. Nevertheless, developing noble-metal-free photocatalysts for efficient solar-to-fuel conversion still remains challenging now. Herein, size-uniform nanoassemblies constructed by ultra-small Zn, Ni-doped CdS nanocrystals and 1T/2H (∼67% 1T phase) oxygen-incorporated MoS2 (O-MoS2) nanosheets were obtained through an ultrasonic water-bath strategy combined with an electrostatic assembly process, which are highly active for visible-light photocatalytic H2 evolution reaction (HER), displaying a superior H2 formation rate of 112.78 mmol·g–1·h–1 (21 times that of Pt–CdS) and the corresponding apparent quantum efficiency (AQE) of 72.0% at 420 nm. The outstanding HER performance originates from the following aspects: First, the interfacial charge transfer and separation between CdS and O-MoS2 are dramatically boosted by the enlarged electron-transfer driving force and the prolonged carrier lifetime via Zn, Ni-doping. Besides, the defect-rich O-MoS2 nanosheets with 1T/2H mixed phases are provided with abundant active sites for H2 production. Moreover, the oxygen incorporation in MoS2 enhances the conductivity and lowers the energy barrier of H2 evolution. The results indicated in this work could offer new ideas for designing novel nanostructures to promote the conversion and utilization of solar energy.