Efficient and Selective CO Reduction to Formate on Pd-Doped Pb (CO ) (OH) : Dynamic Catalyst Reconstruction and Accelerated CO Protonation.

Exploring catalyst reconstruction under the electrochemical condition is critical to understanding the catalyst structure-activity relationship as well as to design effective electrocatalysts. Herein, a PbF nanocluster is synthesized and its self-reconstruction under the CO reduction condition is investigated. F leaching, CO -saturated environment, and application of a cathodic potential induce self-reconstruction of PbF to Pb (CO ) (OH) , which effectively catalyze the CO reduction to formate. The in situ formed Pb (CO ) (OH) discloses >80% formate Faradaic efficiencies (FEs) across a broad range of potentials and achieves a maximum formate FE of ≈90.1% at -1.2 V versus reversible hydrogen electrode (RHE). Kinetic studies show that the CO reduction reaction (CO RR) on the Pb (CO ) (OH) is rate-limited at the CO protonation step, in which proton is supplied by bicarbonate (HCO ) in the electrolyte. To improve the CO RR kinetics, the Pb (CO ) (OH) is further doped with Pd (4 wt%) to enhance its HCO adsorption, which leads to accelerated protonation of CO . Therefore, the Pd-Pb (CO ) (OH) (4 wt%) reveals higher formate FEs of >90% from -0.8 to -1.2 V versus RHE and reaches a maximum formate FE of 96.5% at -1.2 V versus RHE with a current density of ≈13 mA cm .