A/B-Site Management Strategy to Boost Electrocatalytic Overall Water Splitting on Perovskite Oxides in an Alkaline Medium

In this paper, Pr0.7Sr0.3Co1–xRuxO3 perovskite oxides were synthesized by the sol–gel method as bifunctional catalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The overpotentials of PSCR0.05 against HER and OER at 10 mA cm–2 were 319 and 321 mV in alkaline medium, respectively. The Tafel slopes of HER and OER were 87.32 and 118.1 mV/dec, respectively. PSCR0.05 showed the largest electrochemical active area, the smallest charge transfer resistance, and excellent long-term durability. Meanwhile, the PSCR0.05 electrocatalyst was applied for overall water splitting and its cell voltage was maintained at 1.77 V at 10 mA cm–2. The super-exchange interaction between adjacent RuO6–CoO6 octahedra in perovskite made of PSCR0.05 contains sufficient active sites (such as Co2+/Co3+, Ru3+/Ru4+, and O22–/O–). The increase of surface oxygen vacancy and active site is the main reason for the improvement of difunctional catalyst performance. In this work, the electrocatalytic performance of perovskite-type oxides was further optimized by the method of A- and B-site cationic doping regulation, which provides a new idea for perovskite-type bifunctional electrocatalysts.