Formate electrosynthesis from aqueous carbon dioxide over Pb-Zn catalysts with a core-shell structure

Electrocatalytic CO₂ reduction (ECR) has the potential to generate low-carbon fuels that can alleviate energy scarcity and reduce greenhouse gas emissions. In this study, we prepared a range of Pb-Zn bimetallic catalysts with a core-shell structure using a simple chemical reduction technique based on the differing activity characteristics of the metals. The highest faradaic efficiency for formate (FE_formate) was achieved using Pb₃Zn₁ as the catalyst, with a value of 95.3% at -1.26V_RHE in an H-cell (0.5 M KHCO₃) and a current density of 11.18 mA cm^-2. Notably, in the flow-cell (1 M KOH), FE_formate exceeded 90% across a wide potential window, with a maximum FE_formate value of 98.4% being achieved. The excellent catalytic performance of the bimetallic catalyst is attributed to its larger specific surface area and faster ECR kinetics, and the synergistic interaction between Pb and Zn improves the selectivity for formate production.