Facile synthesis of CdS[sbnd]ZnWO4 composite photocatalysts for efficient visible light driven hydrogen evolution

Abstract

The photocatalytic hydrogen evolution has attracted extensive attention owing to the increasing global energy crisis and environmental contamination. In this work, ZnWO4 nanoparticles decorated with CdS nanoparticles were successfully prepared for efficient visible-light photocatalytic hydrogen evolution. The morphological structure, crystal phase, chemical composition and photoelectrochemical performances of the as-prepared CdSZnWO4 composite photocatalysts were investigated by using various characterization techniques. Compared to bare ZnWO4, the CdSZnWO4 composite photocatalysts exhibited stronger visible-light absorption capability and enhanced photocatalytic hydrogen evolution activity under visible light irradiation. The hydrogen production rate of CdSZnWO4 could reach 57.98 μmol/h/g, which was much higher than those of bare ZnWO4 and CdS samples. The enhanced photocatalytic hydrogen evolution activity could be attributed to the formation of heterojunction at the interface between CdS and ZnWO4 in the composite, which would facilitate the photo-generated electron–hole separation and thus improve the photocatalytic activity of ZnWO4. On the basis of photoelectrochemical measurements, a feasible mechanism for enhanced photocatalytic hydrogen evolution of CdSZnWO4 composite photocatalysts was also proposed.