Mapping Spatial and Temporal Electrochemical Activity of Water and CO₂Electrolysis on Gas-Diffusion Electrodes Using Infrared Thermography

Electrolysis of water, CO₂, and nitrogen-based compounds presents the opportunity of generating fossil-free fuels and feedstocks at an industrial scale. Such devices are complex in operation, and their performance metrics are usually reported as electrode-averaged quantities. In this work, we report the usage of infrared thermography to map the electrochemical activity of a gas-diffusion electrode performing water and CO₂reduction. By associating the heat map to a characteristic catalytic activity, the presented system can capture electrochemical and physical phenomena as they occur in electrolyzers for large-scale energy applications. We demonstrate applications for catalyst screening, catalyst-degradation measurements, and spatial activity mapping for water and CO₂electrolysis at current densities up to 0.2 A cm^-2. At these current densities we report catalyst temperature increases (>10 K for 0.2 A cm^-2) not apparent otherwise. Furthermore, substantial localized current density fluctuations are present. These observations challenge assumed local conditions, providing new fundamental and applied perspectives.