Boosting oxygen/hydrogen evolution catalysis via ruthenium doping in perovskite oxide for efficient alkaline water splitting

Recently, perovskite oxides have acquired a rapidly growing research interest in energy storage and conversion systems, especially the electrolysis of water. Rational doping is an extremely effective strategy to enhance the hydrogen evolution reaction/oxygen evolution reaction (HER/OER) of the perovskite oxides. Herein, a series of novel bi-functional electrocatalysts were synthesized by doping Ru in SrFeO3-delta perovskite oxide (SrFe1-xRuxO3-delta, x = 0, 0.15, 0.30, 0.45) which exhibit remarkable enhancements of HER/OER activities and long-term stabilities in the alkaline solution (1.0 M KOH). Among them, SrFe0.7Ru0.3O3-delta (SFR30) shows the best electrocatalytic activities for overall water splitting, exhibiting low overpotentials for HER (-41 mV) and OER (-334 mV) at -10 and 10 mA cm-2, respectively, generating current densities of 10 mA cm-2 in alkaline electrolytic cell using the potential of 1.58 V. In addition, the SFR30 electrocatalyst exhibits remarkable stability which can be operated continuously for 96 h without significant delay. Density functional theory (DFT) calculations indicate that Ru doping can effectively modulate the adsorption of intermediates on the active sites to achieve excellent electrocatalytic performance. Many new prospects have been opened for the development of bi-functional electrocatalysts for overall water splitting.