Bimetal-doped cobalt oxyhydroxides/hydroxides synthesized by electrochemistry for enhanced OER activity†

Abstract

Metal hydroxides and oxyhydroxides are efficient catalysts for electrochemical oxygen evolution reactions. Herein, we employed a Co-MOF with a tunable structure, high porosity and easy preparation as a precursor to synthesize a bimetal-doped oxyhydroxide/hydroxide electrocatalyst by sequential electrochemical-Lewis acid co-etching and electrosorption doping. This unique co-etching method successfully introduced the high-valent metal ion Hf⁴⁺, as well as the electrosorption efficiently doped Fe³⁺, into the catalyst. Experimental studies and theoretical simulations indicate that the introduction of Hf⁴⁺ optimized the OER kinetics, and the introduction of Fe³⁺ lowered the overpotential. This synthetic strategy of doping high-valent metal ions provides a new avenue for designing high-performance electrocatalysts.