High-Quality Cu-Al Nanocrystals for Enhanced CO2 Electroreduction

In the quest to optimise the catalytic activity and selectivity of the CO2 reduction reaction (CO2 RR), various imperfections-such as defects, grain boundaries, and vacancies-pose significant challenges. In a groundbreaking approach, we present the synthesis of well-structured CuAl nanocrystals featuring a preferential (111) crystal facet, a first in the field. This innovative structure not only enhances selectivity but also establishes a clear structure-activity relationship for CO2 RR. The unique properties of CuAl nanocrystals stem from their ability to finely control bonding interactions with CO2 RR intermediates, driven by the synergistic effects of the (111) facet. Utilising a straightforward chemical vapour deposition (CVD) method, we produce these nanocrystals, revealing the atomic distribution of Cu and Al on this dominant surface, which crucially influences CO2 RR performance. Among them, Cu96Al4 achieves the highest Faraday efficiency (FE) for HCOOH (77.71%) and CO (18.01%), attributed to the synergistic effects of Cu and Al arising from the optimal d-band centre of Cu active sites and the strong electron-donating ability of Al. This interaction facilitates the electron transfer from Cu to *COOH, resulting in a high FE for C1 product. Our findings pave the way for advanced catalytic designs that can significantly elevate CO2 conversion efficiencies.