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 (CO 2 RR). It remains a challenge to design the electrolyte compositions for promoting the CO 2 RR. Here, typical anionic surfactants, dodecylphosphonic acid (DDPA) and its analogues, are employed as electrolyte additives to tune the catalysis interface where the CO 2 RR occurs. Surprisingly, the anionic surfactant–tailored interfacial microenvironment enables a set of typical commercial catalysts for the CO 2 RR 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 CO 2 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 CO 2 RR with a pH of 1.5–3.5.