Engineering Multivalent Copper Catalysts From Cu-MOF Towards High-Performance C₂ Electrosynthesis.

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.