Identifying the Activation Mechanism and Boosting Electrocatalytic Activity of Layered Perovskite Ruthenate

Abstract

SrRuO₃ as a rare conductive perovskite ruthenate has attracted increasing attention for application in energy conversion. Here, the electrocatalytic activity for the hydrogen evolution reaction (HER) of thermally synthesized layered SrRuO₃ is investigated and shows a considerable activation during cathodic polarization in alkaline solution. The analysis demonstrates the electrode activation is caused by the increased hydrophilicity of SrRuO₃ surface, revealing the influence of the surface properties on HER performance. For further improving the catalytic activity of perovskite ruthenate, the RuO₂/SrRuO₃ (RSRO) heterostructure is fabricated in situ by reducing the thermal decomposition temperature of 1000 °C for SrRuO₃ to 600 °C. The appropriate lattice parameter of SrRuO₃ ensures a good lattice match, which results in a strong interaction between SrRuO₃ and RuO₂. Hence, the RSRO substantially outperforms the corresponding single-component oxides. In addition, the increased active sites induced by the rapid improvement of hydrophilicity of RSRO surface further highlight its structural advantage for catalytic hydrogen generation. The experimental and theoretical computation results consistently validate the positive synergistic effect among SrRuO₃ and RuO₂ in tuning the atomic and electronic configuration.