Direct conversion of carbon dioxide into multicarbon liquid fuels by the CO2 electrochemical reduction reaction (CO2 RR) can contribute to the decarbonization of the global economy. Here, well-defined Cu2 O nanocubes (NCs, 35 nm) uniformly covered with Ag nanoparticles (5 nm) were synthesized. When compared to bare Cu2 O NCs, the catalyst with 5 at % Ag on Cu2 O NCs displayed a two-fold increase in the Faradaic efficiency for C2+ liquid products (30 % at -1.0 VRHE ), including ethanol, 1-propanol, and acetaldehyde, while formate and hydrogen were suppressed. Operando X-ray absorption spectroscopy revealed the partial reduction of Cu2 O during CO2 RR, accompanied by a reaction-driven redispersion of Ag on the CuOx NCs. Data from operando surface-enhanced Raman spectroscopy further uncovered significant variations in the CO binding to Cu, which were assigned to Ag-Cu sites formed during CO2 RR that appear crucial for the C-C coupling and the enhanced yield of liquid products.
Keywords: CO2 electroreduction; Cu2O; CuAg alloy; operando X-ray absorption spectroscopy; operando surface-enhanced Raman spectroscopy.
© 2021 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.