Modifying the Microenvironment via Triton X-100 to Boost C2+ Production in Electrochemical CO2 Reduction

Abstract The electrochemical CO2 reduction to multi-carbon products represents a promising way for carbon utilization. However, it faces the key challenge of inadequate selectivity and activity. In this work, we introduce a surfactant-assisted strategy to engineer the microenvironment at the electrode/electrolyte interface. By pre-coating the gas diffusion layer with Triton X-100, we were able to regulate the microenvironment of the cathode reaction. This amphiphilic molecule, featuring a hydrophilic head and a hydrophobic tail, establishes a dual-functional microenvironment that ensures an enriched local flux of both CO2 and H2O reactants. Using a Triton X-100-modified gas diffusion electrode, we achieved a Faradaic efficiency for multi-carbon products of 78% at a current density of –200 mA cm–2, representing a 15% enhancement over the unmodified counterpart. In situ Raman and attenuated total reflection infrared spectroscopy further reveal that the Triton X-100 modification strengthens *CO adsorption and promotes *CHO and *OCCHO formation, thereby facilitating C–C coupling and boosting C2+ production.