Tailoring of Metal Boride Morphology via Anion for Efficient Water Oxidation

The metal-metalloid materials have received a massive interest as oxygen-evolving catalysts due to their ability for charge transfer between different elements and modified electronic structures lowering the kinetic energy barriers of the electrochemical processes. Herein, a facile and systematic preparation of metal borides by chemical reduction is reported, with morphologies ranging from nanoparticles to nanosheets which is driven by a careful selection of metal salts solution. The iron doping in cobalt boride nanosheets is found to be an effective approach to further tune the water oxidation activity. The as-prepared catalyst exhibited superior oxygen evolution performance in 1.0 m KOH as the optimized ternary CoFe boride needs an overpotential of 265 mV to achieve a current density of 10 mA cm⁻² at a mass loading of 0.3 mg cm⁻².