Data from: Cu+ transient species mediate Cu catalyst reconstruction during CO2 electroreduction

Understanding metal surface reconstruction during operation is of the uttermost importance in heterogeneous catalysis as it directly affects the available active sites. However, surface reconstruction is notoriously difficult to study because of the dynamic nature of the phenomena behind it. Here, we report on the intermediates, which drive the rearrangement of copper catalysts during the electrochemical CO₂ reduction reaction (CO₂RR). In-situ methods, including mass spectrometry and fluorescence spectroscopy, evidence a dissolution – redeposition process mediated by transient species containing copper in +1 oxidation state. Density functional theory simulations identify copper-adsorbate complexes which form in solution under operating conditions. Copper carbonyls and oxalates are suggested as the major reaction-specific species driving copper reconstruction during CO₂RR. This work motivates future studies to confirm the identity of these compounds and specifically target them to improve the catalyst operational stability.