Plasmon-Assisted Tandem Electrocatalysis for CO2-to-C2H5OH Conversion.

An Ag@AgCu core@satellites electrocatalyst, structured with AgCu alloyed nano-islands dispersed at metallic Ag core surface, was designed to reveal the plasmon-assisted tandem electrochemical CO2 reduction reaction (ECO2RR) for selective C2H5OH production. As unraveled by in situ spectral investigations and theoretical calculations, the core@satellites microstructure enables the tandem ECO2RR pathway to happen at the interfaced Ag and AgCu sites to facilitate C2H5OH formation, with Faradaic efficiency (FE) for C2H5OH reaching 61.4% at -100 mA cm-2. Under light, an intensive localized electric field could be excited in the near-surface region of Ag@AgCu core@satellites, contributing to the increased surface *CO coverage, lowered *COCOH formation barrier and deceased *CHCOH-to-C2H5OH conversion free energy. Thus, a high C2H5OH selectivity (FE = 65.5%) at industrial-level current density (-280 mA cm-2) was achieved over Ag@AgCu core@satellites in a photo-electrochemical flow cell.