Flower-like nanoscale Ni(OH)₂/MnCO₃ electrocatalyst for efficient hydrogen evolution reaction in wide pH range

It is indispensable to develop efficient and cost-effective electrocatalysts, especially those that can work in a wide pH range for the HER (hydrogen evolution reaction) and OER (oxygen evolution reaction). In this study, we have devised a hydrothermal one-pot method for the production of Ni(OH)₂/MnCO₃ composite nanosheets on nickel foam having close resemblance with flowers. The electrocatalyst exhibited appreciable performance for HER with a minimum overpotential of −60 m V and −120 mV in acidic and alkaline media respectively, to deliver 10 mA cm⁻² current density. Tafel slope of 38 mV dec^-1 (in acidic) and 112 mV dec^-1 (in alkaline) medium under a limited potential range of 0 to −0.1 V was observed. The significant performance of such a hybrid system can be attributed to thin sheet morphology, the mutual support of Ni(OH)₂ and Mn(CO₃)₂, and possible generation of active sites at the interface and may contribute to the electrochemically active surface area i.e. 350 cm² (acidic) 190 cm² (alkaline). This study presents a novel approach to pave the way for advanced self-supported nanoscale materials to boost HER in both acidic and alkaline environments.