CdS decorated MnWO4 nanorod nanoheterostructures: a new 0D–1D hybrid system for enhanced photocatalytic hydrogen production under natural sunlight

Abstract

Constructing a heterostructure is an effective strategy to reduce the electron–hole recombination rate, which enhances photocatalytic activity. Here, we report a facile hydrothermal method to grow CdS nanoparticles on MnWO₄ nanorods and their photocatalytic hydrogen generation under solar light. A structural study shows the decoration of hexagonal CdS nanoparticles on monoclinic MnWO₄. Morphological studies based on FE-TEM analysis confirm the sensitization of CdS nanoparticles (10 nm) on MnWO₄ nanorods of diameter-35 nm with mean length ∼100 nm. The lower PL intensity of MnWO₄ was observed with an increasing amount of CdS nanoparticles, which shows inhibition of the charge carrier recombination rate. A CdS@MnWO₄ narrow band gap semiconductor was employed for photocatalytic hydrogen generation from water under solar light and the highest amount of hydrogen, i.e. 3218 μmol h⁻¹ g⁻¹, is obtained which is 21 times higher than that with pristine MnWO₄. The enhanced photocatalytic activity is ascribed to the formation of a CdS@MnWO₄ nanoheterostructure resulting in efficient spatial separation of photogenerated electron–hole pairs due to vacancy defects. More significantly, direct Z-scheme electron transfer from MnWO₄ to CdS is responsible for the enhanced hydrogen evolution. This work signifies that a CdS decorated MnWO₄ nanoheterostructure has the potential to improve the solar to direct fuel conversion efficiency.