Using a pressurized GDE setup to analyze effects of temperature and relative humidity on CO-stripping measurements on a commercial Pt/C ORR catalyst

[Display omitted] •Pressurized GDE setup used to analyze commercial Pt/C ORR catalyst above 100 °C.•CO stripping measurements conducted at 30 °C, 80 °C and 120 °C.•Investigations on effects of temperature and relative humidity on measured electrochemically active surface area (ECSA)•Comparison between Hupd and CO oxidation peak sensitivity at different conditions at 80 °C and 120 °C. This study successfully showcases the capabilities of a newly developed pressurized gas diffusion electrode (GDE) setup by conducting cyclic voltammetry and COstripping measurements at temperatures up to 120 °C, while considering various relative humidity (RH) levels. Our results clearly demonstrate the feasibility of investigating the effects of RH and elevated temperatures above 100 °C using the pressurized GDE setup. In particular, a negative shift in the CO oxidation peak potential upon increasing temperatures is observed, whereas a reduction in RH leads to a positive potential shift of the CO oxidation peak as well as peak broadening. Additionally, our results highlight the heightened sensitivity of the Hupd peak to changes in temperature and RH, resulting in an underestimation of the electrochemically active surface area (ECSA). An essential aspect of this research is the successful replication of trends observed in membrane electrode assembly (MEA) measurements, providing strong validation for the reliability and effectiveness of our pressurized GDE approach as a valuable bridging tool toward MEA testing at elevated temperatures.