Electrostatically Coupled Nanostructured Co(OH)₂–MoS₂ Heterostructures for Enhanced Alkaline Hydrogen Evolution

The development of earth-abundant and highly efficient electrocatalysts for hydrogen evolution reaction (HER) in alkaline media is essential for practical alkaline water electrolysis. The possibility of tuning the electrocatalytic activity of alkaline HER electrocatalysts through various approaches, such as interfacial engineering or doping, has been recently explored. In this work, electrochemically exfoliated Co(OH)2 and chemically derived 1T-MoS2 nanostructures are electrostatically coupled to form a synergistic nanostructured two-dimensional heterostructure, which is shown to remarkably improve the HER activity in an alkaline medium. The Co(OH)2/1T-MoS2 heterostructure with an optimal 1:5 ratio (Co1Mo5) showed a low overpotential of 151 mV at a current density of 10 mA cm–2 and a Tafel slope of 94 mV dec–1 in alkaline media. The shift in the overpotential achieved for the heterostructure (>250 mV) compared to the individual MoS2 component is remarkably high, as per the earlier reports.