Tailoring of Metal Boride Morphology via Anion for Efficient Water Oxidation

Abstract 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 .