Ni0.85Se/MoSe2 Interfacial Structure: An Efficient Electrocatalyst for Alkaline Hydrogen Evolution Reaction

Abstract

Catalyzing hydrogen evolution reaction in alkali media is challenging owing to the sluggish kinetics, originated from the water dissociation process. In this context, synergistic coupling between Ni/Co-based materials with transition metal dichalcogenides (TMDs) often accelerates the alkaline hydrogen evolution reaction (HER). Significant interaction between the two components and active-site density are the keys for achieving a promising catalytic activity. This report emphasizes a two-step selenization approach to prepare a Ni0.85Se/MoSe2 interfacial structure with abundant active sites. Initially, Ni0.75Se nanoparticles were prepared using the solvothermal method and subsequently employed them as a support for the growth of MoSe2 under hydrothermal conditions. This resulted in the formation of a Ni0.85Se/MoSe2 interfacial structure. The results of physical characterization techniques confirm the significant interaction between Ni0.85Se and MoSe2. The interfacial structures showed a superior HER activity in alkali media compared to the individual components; especially, Ni0.85Se/MoSe2 (20) delivers a current density of 10 mA cm–2 at an overpotential of 108 mV. The improved HER activity of the interfacial structure is attributed to the (i) efficient water dissociation process over the Ni0.85Se promoter and (ii) exposure of more catalytic active sites (edges) of MoSe2. In addition, as-prepared Ni0.75Se exhibits a better oxygen evolution reaction (OER) activity by delivering a current density of 10 mA cm–2 at an overpotential of 340 mV. Furthermore, overall water splitting has been demonstrated by constructing an electrolyzer using Ni0.85Se/MoSe2 (20) and Ni0.75Se as a cathode and anode, respectively. The electrolyzer delivers a current density of 10 mA cm–2 at a cell potential of 1.7 V. The long-term stability experiment and the post catalytic characterization reveals the high robustness of the Ni0.85Se/MoSe2 interfacial structure.