Water electrolysis using proton exchange membrane technology offers an ideal process for green hydrogen production, but widespread deployment is inhibited by insufficient catalyst activity, stability and affordability. Iridium-based oxides provide the best overall performance for acidic water oxidation, the limiting reaction for this process, but further improvements are impeded by poor understanding of the restructured active catalyst surface that forms under reaction conditions. Here we present a combination of X-ray and electron scattering data that reveals direct evidence for three paracrystalline structural motifs at the restructured surfaces of highly active catalysts (including rutile IrO₂ and perovskite SrIrO₃) that have previously been described as amorphous. These insights enable the design of a paracrystalline IrO_x catalyst that is independent of the bulk crystalline support and maintains higher activity, longer stability and more effective use of iridium to promote the production of green hydrogen.

使用质子交换膜技术的水电解为绿色氢气生产提供了理想的工艺，但由于催化剂活性、稳定性和经济性不足，其广泛部署受到阻碍。铱基氧化物为酸性水氧化（该过程的限制反应）提供了最佳的整体性能，但由于对反应条件下形成的重组活性催化剂表面了解不足，阻碍了进一步的改进。在这里，我们展示了 X 射线和电子散射数据的组合，揭示了先前被描述为非晶态的高活性催化剂（包括金红石 IrO ₂和钙钛矿 SrIrO ₃ ）重构表面上三种副晶结构图案的直接证据。这些见解使得能够设计一种独立于块状晶体载体的准晶IrO _x催化剂，并保持更高的活性、更长的稳定性和更有效地利用铱来促进绿色氢的生产。