Efficient CO2 electroreduction on facet-selective copper films with high conversion rate.

Tuning the facet exposure of Cu could promote the multi-carbon (C2+) products formation in electrocatalytic CO₂ reduction. Here we report the design and realization of a dynamic deposition-etch-bombardment method for Cu(100) facets control without using capping agents and polymer binders. The synthesized Cu(100)-rich films lead to a high Faradaic efficiency of 86.5% and a full-cell electricity conversion efficiency of 36.5% towards C2+ products in a flow cell. By further scaling up the electrode into a 25 cm² membrane electrode assembly system, the overall current can ramp up to 12 A while achieving a single-pass yield of 13.2% for C2+ products. An insight into the influence of Cu facets exposure on intermediates is provided by in situ spectroscopic methods supported by theoretical calculations. The collected information will enable the precise design of CO₂ reduction reactions to obtain desired products, a step towards future industrial CO₂ refineries. Regulation of Cu facets to promote electrocatalytic CO₂ reduction is interesting and challenging. Here the authors describe a deposition-etch-bombardment synthetic approach to prepare Cu(100)-rich thin film electrodes for CO₂ electroreduction with over 50% ethylene Faradaic efficiency at a total current of 12 A. [ABSTRACT FROM AUTHOR]