High-performance electrocatalytic reduction of CO2 to CO by ultrathin PdCu alloy nanosheets

Electrochemical reduction of carbon dioxide (CO2RR) into fuels and chemicals is a significant step to balance the carbon cycle. For CO2 reduction to CO, the binding energy of intermediates *COOH and *CO is crucial for the electrocatalytic activity and selectivity. Herein, we prepare a series of ultrathin and tunable PdCu alloy nanosheets by a one-pot wet chemistry process and demonstrate that the bimetallic nanosheets can improve the electronic configurations and break the inherent scaling relationship of intermediate binding energy, which leads to a high performance of CO2RR. Specifically, Pd1Cu1 exhibits the best CO2RR performance among the series, with a faraday efficiency (FE) of 97% CO at − 0.80 V vs reversible hydrogen electrode (RHE) in 0.1 M KHCO3 and 96% at − 0.88 V in 1 M KOH with a current density of 521 mA cm−2. This is ascribed to moderate *COOH binding and weak binding of *CO on Pd1Cu1, as manifested in both experimental and theoretical studies. Results from this work highlight the unique potentials of bimetallic alloy nanosheets as high-performance catalysts for electrochemical reduction of CO2.