MoSx@NiO Composite Nanostructures : An Advanced Nonprecious Catalyst for Hydrogen Evolution Reaction in Alkaline Media

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 deposited on NiO nanostructures (MoS @NiO) as a robust catalyst for water splitting is proposed here. NiO nanosponges are applied as cocatalyst for MoS in alkaline media. Both NiO and MoS @NiO composites are prepared by a hydrothermal method. The NiO nanostructures exhibit sponge-like morphology and are completely covered by the sheet-like MoS . The NiO and MoS exhibit cubic and hexagonal phases, respectively. In the MoS @NiO composite, the HER experiment in 1 m KOH electrolyte results in a low overpotential (406 mV) to produce 10 mA cm current density. The Tafel slope for that case is 43 mV per decade, which is the lowest ever achieved for MoS -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 @NiO composite catalysts not only for water splitting, but also for other applications such as lithium ion batteries, and fuel cells