Electrocatalytic CO2 reduction reaction (ECO2RR) stands as a crucial process for converting CO2 into valuable chemicals, particularly C2+ products. Yet, achieving high selectivity towards C2+ chemicals remains challenging. Among the catalysts explored to date, Cu-based catalysts with multivalent Cu are widely used for this process. However, the precise tuning of Cu-based catalysts, especially stabilization of multivalent Cu species, remains a difficult issue for enhancing selectivity toward C2+ products. In this work, we report an efficient Cu-based catalyst (designated as Cu-MOF/CuxO/CF-40), containing Cu-terephthalic acid (PTA) (Cu-MOF) generated on a Cu foil (CF) and CuxO (Cu2+1O and CuO) mainly stemming from Cu-MOF, in achieving ECO2RR to C2 chemicals. The catalyst delivers a total C2 Faradaic efficiency (FEC2) of up to 91.8% and a total current density of 34.6 mA·cm-2 at -1.1 V (vs. RHE) in 0.1 M KCl (H-cell). The Cu2+1O and CuO species, with multivalent Cu properties, adsorb and activate CO2, and improve the electrical conductivity of the catalyst. Cu-MOF stabilizes the multivalent feature and long-term performance of the catalyst. In situ ATR-FTIR and DFT calculations identify *OCCOH as the key C-C coupling intermediate. This work provides a rational design strategy for efficient, stable Cu-based catalysts and demonstrates a single-source route to engineer multivalent Cu sites for selective CO2-to-C2 conversion.
Cao et al. (Mon,) studied this question.