Asymmetric Oxo‐Bridged ZnPb Bimetallic Electrocatalysis Boosting CO2‐to‐HCOOH Reduction

Abstract

Abstract Electrochemical CO2 reduction (ECR) is one of the promising CO2 recycling technologies sustaining the natural carbon cycle and offering more sustainable higher‐energy chemicals. Zn‐ and Pb‐based catalysts have improved formate selectivity, but they suffer from relatively low current activities considering the competitive CO selectivity on Zn. Here, lead‐doped zinc (Zn(Pb)) electrocatalyst is optimized to efficiently reduce CO2 to formate, while CO evolution selectivity is largely controlled. Selective formate is detected with Faradaic efficiency (FEHCOOH) of ≈95% at an outstanding partial current density of 47 mA cm–2 in a conventional H‐Cell. Zn(Pb) is further investigated in an electrolyte‐fed device achieving a superior conversion rate of ≈100 mA cm–2 representing a step closer to practical electrocatalysis. The in situ analysis demonstrates that the Pb incorporation plays a crucial role in CO suppression stem from the generation of the Pb–O–C–O–Zn structure rather than the CO‐boosted Pb–O–C–Zn. Density functional theory (DFT) calculations reveal that the alloying effect tunes the adsorption energetics and consequently modifies the electronic structure of the system for an optimized asymmetric oxo‐bridged intermediate. The alloying effect between Zn and Pb controls CO selectivity and achieves a superior activity for a selective CO2‐to‐formate reduction.

Keywords

• bimetallic electrocatalyst
• CO2 reduction
• electrocatalysis
• formate
• selectivity