Depoisoning Catalysts by Atomic Layer Etching

To improve the sustainability of transition metal catalysts, which suffer from deactivation through poisoning when exposed to sulfur‐containing compounds, atomic layer etch (ALE)—a technique studied predominantly by the microelectronics and semiconductor communities—is explored as a method of regenerating metal catalysts. In this work, the CO 2 reduction reaction (CO 2 RR) through electrolysis over a copper (Cu) catalyst is used as a model system to evaluate the efficacy of the ALE process in de‐poisoning the catalyst studied. Copper surfaces that were poisoned with 1‐dodecanethiol showed reduced faradaic efficiencies for CO 2 RR. Treating the poisoned copper surfaces with an oxygen plasma, the first step of a copper ALE process, restored most of the CO 2 RR catalytic performance. Completing a full ALE cycle using both oxygen plasma and formic acid vapor resulted in further improved CO 2 RR faradaic efficiencies, likely due to the increased surface roughness.