Date

Friday 20 Feb 2026

Time

15:30 - 16:00

Location

BW008

Supervisor

Marc Koper

Jury

Rik Mom

Electrochemical CO2 reduction (CO2R) is a promising strategy for sustainable production of necessary fuels and chemicals which are traditionally derived from fossil resources. Cu remains the only catalyst with significant activity towards the desired C2+ products, such as ethanol and ethylene. However, Cu electrodes universally face severe morphological stability challenges, shifting activity towards hydrogen evolution reaction (HER) and CO production over prolonged operation. Therefore, the mechanism of Cu surface reconstruction is a subject of intense investigation. Investigations using advanced in situ and operando surface science techniques suggest the distinction of two mechanisms of Cu reconstruction, one being driven by the reduction of surface oxides at the onset of CO2R, and the other by the CO2R conditions themselves. Reduction of Cu oxides universally results in surface roughening and creation of undercoordinated sites, which are held responsible for the desired dissociative chemisorption of CO2 and C-C coupling. It remains challenging to rigorously prevent the oxidation of Cu. As a result, exclusion of the oxidation/reduction-driven reconstruction is not trivial and subject of controversy. Recent investigations have characterised Cu surfaces under prolonged CO2R operation on purely metallic Cu. The results have inspired the hypothesis of a dissolution/redeposition mechanism, driven by the formation of [CuCO]+ species. Here, Cu from CO-covered active sites is dissolved, and selectively redeposited onto inactive, bare Cu areas, thus allowing the latter to grow. However, further investigation is needed to validate currently hypothesised deactivation mechanisms of Cu under CO2R conditions.