Modified Cu-Sn Catalysts Enhance CO2RR Towards Syngas Generation

Abstract

The electrochemical reduction in CO2 (CO2RR) to syngas and value-added hydrocarbons offers a promising route for sustainable CO2 utilization. This work develops tuneable Cu-Sn bimetallic catalysts via electrodeposition, optimized for CO2RR in a zero-gap flow cell fed with CO2-saturated KHCO3 solution, a configuration closer to industrial scalability than conventional H-cells. By varying electrodeposition parameters (pH, surfactant DTAB, and metal precursors), we engineered catalysts with distinct selectivity profiles: Cu-Sn(B), modified with DTAB, achieved 50% Faradaic efficiency (FE) to CO at −2.2 V and −50 mA·cm−2, outperforming Ag-based systems that require higher overpotentials. Meanwhile, Cu-Sn(A) favoured C2H4 (35% FE at −100 mA·cm−2), and Cu-Sn(C) shifted selectivity to CH4 (26% FE), demonstrating product tunability. The catalysts’ performance stems from synergistic Cu-Sn interactions and DTAB-induced morphological control, as revealed by SEM/EDX and electrochemical analysis. Notably, all systems operated at lower voltages than literature benchmarks while maintaining moderate CO2 utilization (32–49% outlet). This study highlights the potential of electrodeposited Cu-Sn catalysts for energy-efficient CO2RR, bridging the gap between fundamental research and industrial application in syngas and hydrocarbon production.