Tailoring dendritic architecture and interfacial properties of bimetallic electrocatalysts for CO₂ electroreduction in amine-based capture media

The integration of CO 2 capture and electrochemical conversion has emerged as a promising strategy for simultaneously mitigating carbon emissions and producing value-added chemicals, with amine-based capture electrolytes offering an attractive platform for direct CO 2 utilization. However, the limited availability of electroactive free molecular CO₂ and the competing hydrogen evolution reaction (HER) continue to restrict conversion efficiency and product selectivity. Herein, a binder-free dendritic Pb–Sn bimetallic electrode was developed to promote selective CO 2 -to-formate conversion in a 30 wt.% monoethanolamine (MEA) capture electrolyte. The optimized Pb₅Sn₁₅ electrode achieved a Faradaic efficiency of 86.5% and a formate partial current density of 27.3 mA cm⁻² at −1.1 V versus RHE. The enhanced catalytic performance is attributed to the synergistic effects of the dendritic Pb–Sn architecture, alloy-induced electronic redistribution that preferentially stabilizes the ⁎OCHO pathway, continuous regeneration of free molecular CO 2 through the reversible MEA–carbamate equilibrium, and the formation of a dense electrical double layer at the electrode–electrolyte interface. Together, these features facilitate efficient reactant transport, accelerate interfacial charge transfer, suppress the competing HER, and promote highly selective formate production. This work provides new insights into the interfacial mechanisms governing integrated CO 2 capture and electrochemical conversion and establishes dendritic Pb–Sn bimetallic electrodes as highly efficient electrocatalysts for direct CO 2 -to-formate conversion in amine-based capture media.