Progress in nickel chalcogenide electrocatalyzed hydrogen evolution reaction

Electrochemical water splitting powered by electrical energy derived from renewable sources is a green and faster way of producing bulk hydrogen with the highest purity. Unfortunately, the cost-inefficiency associated with energy loss (as overpotential) and costs of electrode materials have been forbidding this technology to surpass the currently dominant industrial process (steam reforming of hydrocarbons). With the recent evolution of transition metal chalcogenides, efficient commercial electrochemical water splitting is not too far. Transition metal chalcogenides are better in the hydrogen evolution reaction (HER) than pristine metals as they have negatively polarized chalcogenide anions with relatively lower free energy for proton adsorption. Moreover, chalcogenides are relatively easy to prepare and handle. Several metal chalcogenides have been reported with good HER activity among which Ni chalcogenides are reported to be exceptional ones. In recent years, growth of the nickel chalcogenide catalysed HER is massive. This review is devoted to bringing out a comprehensive understanding of what had happened in the recent past of this field with highlights on future prospects. In addition, we have also briefed the key physico-chemical properties of these materials and highlighted what one should anticipate while screening an electrocatalyst for electrochemical water splitting.