MoS<i>_x</i>@NiO Composite Nanostructures: An Advanced Nonprecious Catalyst for Hydrogen Evolution Reaction in Alkaline Media

Abstract

Abstract The design of the earth‐abundant, nonprecious, efficient, and stable electrocatalysts for efficient hydrogen evolution reaction (HER) in alkaline media is a hot research topic in the field of renewable energies. A heterostructured system composed of MoS x deposited on NiO nanostructures (MoS x @NiO) as a robust catalyst for water splitting is proposed here. NiO nanosponges are applied as cocatalyst for MoS 2 in alkaline media. Both NiO and MoS 2 @NiO composites are prepared by a hydrothermal method. The NiO nanostructures exhibit sponge‐like morphology and are completely covered by the sheet‐like MoS 2 . The NiO and MoS 2 exhibit cubic and hexagonal phases, respectively. In the MoS x @NiO composite, the HER experiment in 1 m KOH electrolyte results in a low overpotential (406 mV) to produce 10 mA cm −2 current density. The Tafel slope for that case is 43 mV per decade, which is the lowest ever achieved for MoS 2 ‐based electrocatalyst in alkaline media. The catalyst is highly stable for at least 13 h, with no decrease in the current density. This simple, cost‐effective, and environmentally friendly methodology can pave the way for exploitation of MoS x @NiO composite catalysts not only for water splitting, but also for other applications such as lithium ion batteries, and fuel cells.