Strain heterogeneity in RuO2 for efficient acidic oxygen evolution reaction in proton exchange membrane water electrolysis

Developing acid-stable and active ruthenium dioxide (RuO2) catalysts for the oxygen evolution reaction (OER) is crucial for facilitating the large-scale applications of proton exchange membrane water electrolysis (PEMWE) for hydrogen production. Here, we propose a strain heterogeneity engineering strategy to simultaneously enhance the OER stability and activity of RuO2 electrocatalysts by introducing single-atom platinum (Pt). In a PEM water electrolyzer, the resultant Pt-RuO2 catalyst archives 3 A cm−2 at a low voltage of 1.791 V and maintains a stable performance for over 500 h at 500 mA cm−2. These performance metrics highlight its potential for practical applications. Experiments and calculations analyses confirm that the bulk tensile strain effectively stabilizes the entire structure of electrocatalysts, while the regions of compressive strain are identified as highly active catalytic sites, where the weakened binding energy of oxo-intermediates improves the catalytic activity. Efficient and stable catalysts are essential for advancing proton exchange membrane water electrolysis. In this study, a strain heterogeneity engineering strategy with single Pt atoms is used to enhance the activity and stability of RuO2 for the oxygen evolution reaction.