Boosting Pd-catalysis for electrochemical CO2 reduction to CO on Bi-Pd single atom alloy nanodendrites

Pd is a catalyst for electrochemical CO2 reduction to CO but often disturbed by H2 and formate formation at low overpotentials due to its strong affinity to H atoms. Herein, guided by density functional theory (DFT) calculations, Bi-Pd single atom alloy (SAA) nanodendrites (NDs) with Bi atomically dispersed in Pd matrices have been developed for efficient CO2 reduction to CO. The Faradic efficiencies (FEs) of CO on the Bi6Pd94-SAA ND catalyst reach 90.5 % and 91.8 % in H-type and gas diffusion flow cells with overpotentials of only 290 and 200 mV, respectively, which are among the best of the reported Pd-based electrocatalysts. The greatly enhanced CO formation on the Bi6Pd94-SAA NDs can be attributed to the increased reaction barriers for H2 formation due to a lower H coverage resulted from Bi doping, and the decreased free energy for *COOH generation which is a key intermediate for CO production.