Conversion of Iron Ore into an Active Catalyst for the Oxygen Evolution Reaction

Abstract The storage of electricity from intermittent renewable energy sources in the form of hydrogen via water electrolysis is an attractive approach to reducing CO₂ levels, as well as powering future transportation with hydrogen fuel cells. Earth‐abundant transition metal oxide like materials are synthesized and extensively studied in research laboratories to replace expensive IrO₂ and RuO₂ anodes for the oxygen evolution half reaction. However, pristine materials mined from the earth's crust are yet to be explored for such an application. Here the electrocatalytic activity of iron ore is investigated and a novel approach is reported to significantly improve its catalytic properties via formation of a nickel hydroxide layer on the surface. This electrocatalyst achieves a current density of 10 mA cm⁻² at a low overpotential of 280 mV and maintains its activity for extended periods of electrolysis under alkaline conditions. This simple process to convert an abundant commodity into a value‐added product should be of considerable interest.