Anionic Surfactant-Tailored Interfacial Microenvironment for Boosting Electrochemical CO2 Reduction.

Abstract

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% FECO 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.