Abstract 

The electrochemical CO₂ reduction reaction (CO₂RR) offers the opportunity to convert CO₂ into fuels and chemical feedstocks, while mitigating anthropogenic CO2₂ emissions and storing renewable energy. Multi-carbon (C₂₊) compounds (e.g., ethylene, ethanol, propanol) are among the most attractive CO₂RR products owing to their commercial value and high energy densities. However, optimizing the selectivity of CO₂RR electrocatalysts towards one particular product remains a crucial challenge that is not trivial to address because multiple intermediates are involved in the CO₂ to C₂₊ conversion pathway.

In these contexts, unambiguous relationships between the activity, selectivity, and stability of the catalyst with its structure and composition become crucial to make concrete progress in this field.

In this talk, I will showcase a few examples which highlight how shape-controlled nanocrystals can contribute to addressing the selectivity challenge in CO₂RR. First of all, I will discuss how size control of Cu nanocubes and Cu octahedra has revealed the importance of facet-ratio to maximize the selectivity towards ethylene and methane, respectively. Second, I will present our recent computational-experimental efforts towards using well-defined NCs, in the framework of a tandem scheme based on the coupling of Cu nanocrystals with CO-generating Ag, to elucidate selectivity rules at the hydrocarbons/alcohols branching nodes in the CO₂RR pathway and increase ethanol production. Finally, I will discuss a few examples of Cu-based bimetallic catalysts which evidence the opportunities and challenges in this area.