| Abstrakt: |
The electroreduction of CO2into value-added liquid fuels holds great promise for addressing global environmental and energy challenges. However, achieving highly selective yielding of multi-carbon oxygenates through the electrochemical CO2reduction reaction (eCO2RR) is a formidable task, primarily due to the sluggish asymmetric C–C coupling reaction. In this study, a novel metal–organic framework (CuSn–HAB) with unprecedented heterometallic Sn···Cu dual sites (namely, a pair of SnN2O2and CuN4sites bridged by μ-N atoms) was designed to overcome this limitation. CuSn–HABdemonstrated an impressive Faradic efficiency (FE) of 56(2)% for eCO2RR to alcohols, achieving a current density of 68 mA cm–2at a low potential of −0.57 V (vs RHE). Notably, no significant degradation was observed over a continuous 35 h operation at the specified current density. Mechanistic investigations revealed that, in comparison to the copper site, the SnN2O2site exhibits a higher affinity for oxygen atoms. This enhanced affinity plays a pivotal role in facilitating the generation of the key intermediate *OCH2. Consequently, compared to homometallic Cu···Cu dual sites (generally yielding ethylene product), the heterometallic dual sites were proved to be more thermodynamically favorable for the asymmetric C–C coupling between *CO and *OCH2, leading to the formation of the key intermediate *CO–*OCH2, which is favorable for yielding ethanol product. |
