Efficient hydrogen evolution reaction performance of Ni substituted WS2 nanoflakes

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.