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

[Display omitted] •Ru-doped SrFe1-xRuxO3-δ perovskite oxides were successfully fabricated through a modified sol–gel method.•The SrFe0.7Ru0.3O3-δ exhibits significantly enhanced bifunctional electrocatalytic activities for HER and OER in alkaline electrolytes.•The DFT studies demonstrate Ru doping optimizes the electronic structure of SrFe0.7Ru0.3O3-δ and thus improves the charge transfer efficiency.•An electrolyzer with SFR30 as both the anode and cathode catalysts requires only a cell voltage of 1.58 V vs. RHE to drive a current density of 10 mA cm−2 in an alkaline medium. 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-δ perovskite oxide (SrFe1-xRuxO3-δ, 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-δ (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.