Decoupling degradation and (bi)carbonate precipitation during pulsed electrochemical CO2 reduction

Electrochemical CO2 reduction (eCO2R) is a promising pathway to convert detrimental CO2 emissions into sustainable fuels and chemicals. The use of gas diffusion electrodes (GDEs), in which CO2 is supplied directly from the gas phase, enables achieving remarkable activity and product selectivity. Despite these progresses, GDEs undergo fast degradation during eCO2R (10s hours) due to the precipitation of hygroscopic (bi)carbonate crystals within the GDE caused by excessive CO2 dissolution. Stability can be improved by regularly interrupting the eCO2R (pulsed electrolysis), even though the reason behind the improvement is still unclear. Here, we propose to employ operando wide-angle X-rays scattering to study (bi)carbonate precipitation, (bi)carbonate re-dissolution during pulsed electrolysis using variable pulse lengths, frequencies, and voltages. Our results will provide important understanding of GDE degradation processes, as well as relevant guidelines for technological advances.