Potentiodynamic methods inducing structural changes in Cu catalysts for electrochemical CO₂ reduction (CO₂RR) are promising for steering catalyst selectivity toward multi-carbon products. This study uses in situ scanning tunneling microscopy (STM), surface X-ray diffraction (SXRD), and Raman spectroscopy to show that low-coordinated Cu surface species spontaneously form near the onset of CO₂ electrocatalytic reduction. CO-induced Cu nanocluster formation leads to irreversible surface restructuring, persisting over a wide potential range. Upon potential increase, these nanoclusters disperse into Cu adatoms stabilizing reaction intermediates. This self-induced formation of undercoordinated sites explains the catalyst's reactivity and can be exploited to regenerate active CO₂RR sites.

Reihaneh Amirbeigiarab, Jing Tian, Antonia Herzog, Canrong Qiu, Arno Bergmann, Beatriz Roldan Cuenya, Olaf M. Magnussen