Efficient and Selective CO₂ Reduction to Formate on Pd‐Doped Pb₃(CO₃)₂(OH)₂: Dynamic Catalyst Reconstruction and Accelerated CO₂ Protonation

Abstract

Abstract 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 2 nanocluster is synthesized and its self‐reconstruction under the CO 2 reduction condition is investigated. F − leaching, CO 2 ‐saturated environment, and application of a cathodic potential induce self‐reconstruction of PbF 2 to Pb 3 (CO 3 ) 2 (OH) 2 , which effectively catalyze the CO 2 reduction to formate. The in situ formed Pb 3 (CO 3 ) 2 (OH) 2 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 2 reduction reaction (CO 2 RR) on the Pb 3 (CO 3 ) 2 (OH) 2 is rate‐limited at the CO 2 protonation step, in which proton is supplied by bicarbonate (HCO 3 − ) in the electrolyte. To improve the CO 2 RR kinetics, the Pb 3 (CO 3 ) 2 (OH) 2 is further doped with Pd (4 wt%) to enhance its HCO 3 − adsorption, which leads to accelerated protonation of CO 2 . Therefore, the Pd‐Pb 3 (CO 3 ) 2 (OH) 2 (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 −2 .