Controlling C-C coupling in electrocatalytic reduction of CO₂ over Cu_1-Zn/C

From the perspective of sustainable environment and economic value, the electroreduction of CO₂ to higher order multicarbon products is more coveted than that of C₁ products, owing to their higher energy densities and a wider applicability. However, the reduction process remains extremely challenging due to the bottleneck of C-C coupling over the catalyst surfaces, and therefore designing a suitable catalyst for efficient and selective electrocatalytic reduction of CO₂ is a need of the hour. With the target of producing C₃₊ products with higher selectivity, in this study we explored the nano-alloys of Cu_1-Zn as electrocatalysts for CO₂ reduction. The nano-alloy Cu_1-Zn synthesized from the corresponding bimetallic metal organic framework materials demonstrated a gradual enhancement in the selectivity of acetone upon CO₂ electroreduction with higher doping of Zn. The Cu_1-Zn alloy opened up a wide possibility of fine-tuning the electronic structure by shifting the position of the d-band centre and modulating the interaction with intermediate CO and thus enhanced the selectivity of desirable products, which might not have been accessible otherwise. The postulated molecular mechanism of CO₂ electroreduction involving the desorption of the poorly adsorbed intermediate CO due to the presence of Zn and spilling over of free CO to Cu sites in the nano-alloy Cu_1-Zn for further C-C coupling to yield acetone was corroborated by the first principles studies.