Enhancing CO2 Electroreduction to Ethylene via Copper−Silver Tandem Catalyst in Boron‐Imidazolate Framework Nanosheet

Copper‐based tandem catalysts with a well‐defined Cu coordination environment for the electrochemical CO2 reduction reaction (CO2RR) are highly desirable, due to their unique geometric‐electronic properties and helpfulness for revealing structure–property correlations. Here, this work synthesizes a tandem catalyst at atomic configuration scale, Ag@BIF‐104NSs(Cu), by using the ultrathin boron imidazolate framework (BIF) nanosheets as support to load Ag nanoparticles (NPs). Due to the highly ordered benzoate ligands decorated on the Cu sites of BIF‐104NSs(Cu), Ag NPs are located in atomic proximity to Cu sites via a coordination effect. Electrochemical CO2RR measurements show this tandem catalyst highly improves the selectivity and activity for the CO2 reduction to ethylene. The faradaic efficiency (FEC2H4) of 21.43% is significantly higher than that of BIF‐104NSs(Cu) (3.82%). Further, density functional theory calculations reveal that the Ag sites in the composite can efficiently reduce CO2 to *CO, that subsequently migrate to the Cu sites. Thereafter, the Cu–Ag atom pair is responsible for the C–C coupling of the local enriched *CO and further formation of C2H4. A copper‐silver tandem catalyst is synthesized at atomic configuration scale, by using the ultrathin boron imidazolate framework (BIF) nanosheets as support to load Ag nanoparticles (NPs). Ag@BIF‐104NSs(Cu) shows higher catalytic activity and selectivity for C2H4 than BIF‐104NSs(Cu), because the Cu–Ag atom pair can effectively enhance the C–C coupling of the local enriched *CO from Ag sites.