Cobalt-Boride: An efficient and robust electrocatalyst for Hydrogen Evolution Reaction

This work presents Cobalt-Boride (Co-B) as a non-noble, efficient and robust electrocatalyst for Hydrogen Evolution Reaction (HER) active in aqueous solution of wide pH values. In neutral solution, amorphous Co-B nanoparticles (30-50 nm size) generate high current density (10 mA/cm(2)) at low overpotential (250 mV) with Tafel slope of 75 mV/dec following Volmer-Heyrovsky reaction mechanism. Highly active Co surface sites created by electronic transfer from B to Co (as inferred from XPS analysis and supported by theoretical calculations) are responsible for this significant HER activity in wide range of pH (4-9) values. Stability and reusability tests also demonstrate the robust nature of the catalyst.