Structural aspects of oxygen evolution reaction catalyst support materials: Identifying the most important factors for catalytic performance

Proton exchange membrane water electrolyzers have emerged as promising energy conversion and storage systems in the global pursuit of climate goals. However, in order to have a broad market ramp-up for this technology, the catalyst materials especially for the rate determining reaction, the oxygen evolution reaction (OER), need to be optimized to reduce the amount of critical raw materials. In this work, we investigated various antimony doped tin oxides (ATO) structures to identify the optimal configuration that maximizes support functionality. Through systematic physical as well as electrochemical investigations, the results of this work indicate that specific ATO structures exhibit superior performance and provide enhanced conductivity and activity for OER catalysts. This research highlights the importance of tailoring the ATO structure to achieve optimal support characteristics that ultimately contribute to the overall efficiency and durability of the catalyst system. • ATO structure optimized by tuning Sb doping level, calcination temperature, and drying method. • Optimal conditions: 7 mol-% Sb doping and 550 °C calcination temperature for best performance. • Freeze drying gave the smallest crystal sizes and best conductivity, supercritical drying the largest area. • Catalyst supported on freeze dried ATO surpassed commercial IrO 2 in mass activity in the single cell.