Poly(ionic liquid)-based bimetallic tandem catalysts for highly efficient carbon dioxide electroreduction

Poly(ionic liquid)-metal (PIL-metal) hybrids were developed as a platform for facilely constructing tandem catalysts to reach highly efficient electrocatalytic reduction of CO2 (CO2RR). By introducing extra metal with distinct CO2RR response to Cu-PIL hybrids, Cu@PIL@Ag and Cu@PIL@Bi were obtained. Remarkably, Cu@PIL@Ag exhibits an excellent C2+ Faradaic efficiency (FEC2+) of 83.2% with a high partial current density (jC(2+)) of 416.1 mA cm(-2) in 3 M KOH and an even higher jC2+ (708.9 mA cm(-2)) in 1 M KOH, while Cu@PIL@Bi possesses high FEC1 (> 60%) and low FEC2+ (< 5%) in a wide potential range. Mechanistic studies demonstrate the output of such a tandem system, either synergistic or maladjusted, depends on not only CO2RR response of Ag and Bi but also specific Cu-Ag and Cu-Bi interactions. Besides, the PIL layer could adjust the reactivity by promoting the dispersion and availability of active sites and enriching the local key intermediates.