Water electrolysis is a very promising technology for sustainable hydrogen generation using renewable electrical energy. The excellent performance and dynamic behavior for storing electrical energy in hydrogen allow polymer electrolyte membrane (PEM) electrolysis to cover the gap between the intermittent renewable power production and the grid demand at different time horizons and scales. This work is addressed to the development and characterization of high performance nanostructured Ir-Ru-oxide electro-catalyst achieving for the rate determining oxygen evolution reaction a current density of 3 A cm⁻² at about 1.8 V (> 80% enthalpy efficiency) with a low catalyst loading (0.34 mg cm⁻²). The stability characteristics were studied in practical PEM electrolysis cells operating at 80 °C, using several durability tests of 1000 h each to evaluate the reliability of this electro-catalyst for real-life operation. Further insights on the degradation mechanism were acquired by subjecting the catalyst to potential steps in a specially designed electrochemical flow cell under corrosive liquid electrolyte with on-line monitoring of the dissolved ions. Structural, morphology, composition and surface analysis of the anode electro-catalyst after operation in the electrolysis cell, complemented by in-situ electrochemical diagnostics, provided important insights into the degradation mechanisms. Catalyst operation at high turnover frequency (TOF) was observed to cause a progressive change of Lewis acidity characteristics with time for both Ir and Ru cations thus influencing their ability to promote water oxidation.

水电解是使用可再生电能可持续产生氢的非常有前途的技术。用于在氢气中存储电能的出色性能和动态行为使聚合物电解质膜（PEM）电解能够覆盖间歇性可再生能源发电量和在不同时间范围和尺度下的电网需求之间的差距。这项工作致力于开发和表征高性能纳米结构Ir-Ru-氧化物电催化剂，该催化剂在大约1.8 V（> 80％的焓效率）下以3 A cm ^-2的电流密度实现了确定析氧反应的速率。催化剂负载量低（0.34 mg cm ^-2）。在80°C下运行的实际PEM电解槽中研究了稳定性特性，使用了几个1000 h的耐久性测试来评估这种电催化剂在实际操作中的可靠性。通过对催化剂进行专门设计的电化学流通池，在腐蚀性液体电解质下，对溶解离子进行在线监测，可以对催化剂进行潜在的处理，从而获得有关降解机理的更多见解。在电解池中运行后，阳极电催化剂的结构，形态，组成和表面分析，再加上原位电化学诊断，为降解机理提供了重要的见识。