Solution-based synthesis of NiS/CdS nanocomposite heterojunction for efficient visible-light-driven hydrogen evolution

Abstract

Hydrogen (H2) generation represents the fruitful fuel for the future as an alternative, clean, and light source of energy. The production of H2 from water-based solutions via photocatalysis is an alternate method. This study aimed at the efficient generation of H2 over the nanostructured CdS nanorods coupled with a different amount (3.0–12.0 wt%) of NiS nanoparticles to form visible-light active nanocomposites. The formed materials exhibited mesoporous surface texture with high surface areas of 112–125 m2 g−1 which is close to the parent CdS (125 m2 g−1). Also, the introduction of NiS to CdS revealed the augmentation of visible-light harvesting and bandgap lessening from 2.49 for pure CdS to 1.99 eV for 9.0% NiS/CdS nanocomposites. The evolution of hydrogen by photocatalytic decomposition of glycerol in water on NiS/CdS in the presence of a trace amount of hexa-chloroplatinic acid as hole scrounger and cocatalyst precursor was achieved. The 9% NiS/CdS substantiated greater H2 production of 2823.4 μmol g−1h−1, a >five-times and >twenty-times greater than the pristine CdS and NiS, respectively for the tuned dose of 1.2 gL‒1 and magnificent recyclability for five runs. The imaginative light absorbance and overall bandgap reduction due to the formation of the stable p-n junction have a key role in the enhanced separation of the photogenerated charge carriers that lead to efficient photocatalytic H2 production.