Dopant-Induced Surface Self-Etching of Cobalt Carbonate Hydroxide Boosts Efficient Water Splitting

Graphical Losing it : A catalyst surface self-etching strategy is suggested to construct the high-performance V−CoCH catalyst for the overall water splitting. With the easy and partial dissolution of V species in the early stages of the oxygen evolution reaction, a large number of active sites and oxygen vacancies are generated, and the electrochemical activity is improved significantly. Herein, vanadium-doped cobalt carbonate hydroxide, V−CoCH, was synthesized as efficient catalyst for water splitting. Vanadium species were partially dissolved in the early stages of the oxygen-evolution reaction (OER), inducing self-etching of the catalyst surface, which is helpful for catalyst surface reconstruction and resulted in a higher number of active sites and oxygen vacancies. The synergy between V-doping and oxygen vacancies improved the catalytic activity: V−CoCH showed an exceptional OER catalytic performance with an overpotential of 183 mV at 10 mA cm −2 . The water-splitting cell consisting of V−CoCH only required 1.52 V to reach 10 mA cm −2 . Theoretical calculations revealed that vanadium in V−CoCH played an important role in electron regulation of active sites. The oxygen vacancies had an important effect on improvement of the OER performance through not only the exposure of more active sites but also through modulation of the electronic structure. This work provides an effective strategy for constructing high-performance electrocatalysts.