High resistance towards electrochemical dissolution of cubic Rh@Ir core shell in acidic water splitting

The industrial development of acidic water splitting significantly counts on the activity associated with stability of oxygen evolution reaction (OER) electrocatalyst. In this work, we have constructed cubic Rh@Ir core–shell for acidic water splitting. The formed Rh@Ir electrocatalyst shows a high HER performance with only 29 mV overpotential for 10 mA cm −2 , stemming from the upshifted and downshifted d band center of Ir and Rh, leading to a moderate hydrogen binding strength. The Ir atom donates its electrons to nearby Rh atoms triggering a high susceptibility in nucleophilic attack by H 2 O to generate *OOH; thereby, the overpotential required to achieve 10 mA cm −2 is 216 mV for Rh@Ir core–shell, better than commercial IrO 2 . Moreover, the stability is superior to commercial IrO 2 and pure Ir electrocatalyst due to the strong electronic interplay in Rh@Ir contributing to a better resistance towards electrochemical dissolution proved by operando Raman and electrochemical impedance spectroscopies. Only 1.55 V is needed for Rh@Ir to drive overall water splitting at 10 mA cm −2 .