Temperature-dependent mechanism evolution on RhRu3Ox for acidic water oxidation

The oxygen evolution reaction, as the anodic reaction of many electrochemical devices, plays a crucial role in energy conversion. However, the insufficient stability of non-iridium-based materials during the oxygen evolution reaction has severely limited the large-scale application of such devices. Here, using a home-made operando differential electrochemical mass spectrometry system, we show a temperature dependent mechanism evolution effect of RhRu₃O_x in the oxygen evolution process, which highlights the role of temperature in triggering mechanism evolution. This effect enriches the strategies for pathway manipulation. Since different kinetic pathways can influence catalyst stability, this finding suggests that temperature-dependent pathway regulation may serve as an approach to optimize stability. To evaluate the potential of RhRu₃O_x for practical applications, we assemble it into a proton exchange membrane electrolyzer and demonstrate its stability at room temperature for over 1000 hours at a current density of 200 mA cm^-2. Density functional theory studies suggest that the existence of a kinetic barrier related to lattice oxygen activation might be the reason for the observed temperature dependent behavior of RhRu₃O_x at elevated temperatures.