Efficient hydrogen evolution reaction performance of Ni substituted WS2 nanoflakes

Abstract

We have investigated the structural, optical and electrocatalytic hydrogen evolution reaction (HER) performance of pristine, Co and Ni substituted WS₂ nanoflakes synthesised by facile hydrothermal method. The XRD pattern confirms the formation of hexagonal WS₂ for both pristine and substituted WS₂ nanoflakes. The FESEM images validate the flake-like structure for both pristine and substituted WS₂. In addition, we have also analysed the Raman and UV-Vis absorbance spectra of the samples. The electrocatalytic studies reveal that the nickel-substituted WS₂ (Ni-WS₂) nanoflakes show superior hydrogen evolution (HER) performance compared to cobalt-substituted WS₂ (Co-WS₂) nanoflakes. Hence, we have varied the Ni concentration and investigated the dependence of Ni content on the electrocatalytic performance. It is found that the electrocatalytic performance of the Ni-WS₂ nanoflakes increases with an increase in Ni content owing to the modified edge structures. Thus, our studies suggest Ni substitution in WS₂ nanostructures can boost electrocatalytic HER performance.