Tuning carbon dioxide electroreduction through selective facet exposure

The carbon dioxide reduction reaction (CO₂RR) could reduce the atmospheric CO₂ and store the excess energy obtained by renewable sources. However, proper catalysts are sought to reduce the high overpotentials needed to electroreduce CO₂ and improve the selectivity toward a desired product. Through rational synthetic control, it is possible to obtain nanocrystals (NCs) with a certain shape, which is translated into a preferential surface orientation. Given the structure sensitivity of the CO₂RR, the use of shape-controlled NCs allows for tuning the activity and selectivity of the reaction. This review analyzes the recent findings about shape-controlled NCs for the CO₂RR regarding their synthesis, shape-dependent selectivity, and how to twist their catalytic behavior and stability by compositional modifications. The importance of combining in situ and operando techniques that enable proper correlations between the structural and compositional changes of the catalyst under CO₂RR conditions, and the resulting product distribution is highlighted, aiming for a final transference to real application systems.