To date, copper is the only monometallic catalyst that can electrochemically reduce CO2 into high value and energy‐dense products, such as hydrocarbons and alcohols. In recent years, great efforts have been directed towards understanding how its nanoscale structure affects activity and selectivity for the electrochemical CO2 reduction reaction (CO2RR). Furthermore, many attempts have been made to improve these two properties. Nevertheless, to advance towards applied systems, the stability of the catalysts during electrolysis is of great significance. This aspect, however, remains less investigated and discussed across the CO2RR literature. In this Minireview, the recent progress on understanding the stability of copper‐based catalysts is summarized, along with the very few proposed degradation mechanisms. Finally, our perspective on the topic is given.

To date, copper is the only monometallic catalyst that can electrochemically reduce CO2 into high value and energy‐dense products, such as hydrocarbons and alcohols. In recent years, great efforts have been directed towards understanding how its nanoscale structure affects activity and selectivity for the electrochemical CO2 reduction reaction (CO2RR). Furthermore, many attempts have been made to improve these two properties. Nevertheless, to advance towards applied systems, the stability of the catalysts during electrolysis is of great significance. This aspect, however, remains less investigated and discussed across the CO2RR literature. In this Minireview, the recent progress on understanding the stability of copper‐based catalysts is summarized, along with the very few proposed degradation mechanisms. Finally, our perspective on the topic is given.

Copper is still the monometallic electrocatalyst of choice for electrochemical reduction of CO 2 (ERC) when added-value products, such as hydrocarbons and alcohols, are desired. However, severe morphological and structural changes are observed upon exposure to the ERC operation conditions. One of the pending questions in the community is what the mechanism behind this reconstruction is. In the present study, pulse-electrodeposited copper nanoparticles were exposed to different ERC relevant reductive potentials and tracked with identical location scanning electron microscopy (IL-SEM). This approach provides information on the morphological and structural history and subsequent change of Cu nanoparticles and with that a deep insight into the reconstruction events. With this evidence, we could interpret the observed structural changes as two separate electrochemical processes occurring one after another, namely copper dissolution from pre-oxidized native nanoparticles and subsequent (electro-) redeposition of the dissolved copper species in a form of new smaller Cu fragments.

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