Anionic Surfactant-Tailored Interfacial Microenvironment for Boosting Electrochemical CO₂ Reduction

Both the catalyst and electrolyte deeply impact the performance of the carbon dioxide reduction reaction (CO₂RR). It remains a challenge to design the electrolyte compositions for promoting the CO₂RR. Here, typical anionic surfactants, dodecylphosphonic acid (DDPA) and its analogues, are employed as electrolyte additives to tune the catalysis interface where the CO₂RR occurs. Surprisingly, the anionic surfactant-tailored interfacial microenvironment enables a set of typical commercial catalysts for the CO₂RR to deliver a significantly enhanced selectivity of carbon products in both neutral and acidic electrolytes. Mechanistic studies disclose that the DDPA addition restructures the interfacial hydrogen-bond environment via increasing the weak H-bonded water, thus promoting the CO₂ protonation to CO. Specifically, in an H-type cell, the Faradaic efficiency of CO increases from 70 to 98% at -1.0 V versus the reversible hydrogen electrode. Furthermore, in a flow cell, the DDPA-containing electrolyte maintains over 90% FE_CO from 50-400 mA cm^-2. Additionally, this electrolyte modulation strategy can be extended to acidic CO₂RR with a pH of 1.5-3.5.