Catalyst-Electrolyte Interface Engineering Propels Progress on Acidic CO2 Electroreduction

Abstract

Electrocatalytic carbon dioxide reduction (CO2RR) presents a viable strategy to transfer the dominant greenhouse gas, CO2, into high-value-added chemicals, supporting carbon neutrality. CO2RR in alkaline and neutral media have thrived in recent years due to their high CO2 solubility and favourable CO2 activation ability. However, critical challenges have emerged, such as carbonate formation and subsequent CO2 crossover to anodic sides, which undermine carbon efficiency and system stability. Acidic media provides an advantageous environment to prevent CO2 crossover into the anolyte but suffers from strong HER competition which is significantly more active in acidic conditions, largely reducing CO2 conversion efficiency. Research on acidic CO2RR began with some basic studies, including testing various catalysts and electrolytes and designing diverse substrate structures. With advancements in characterization technologies, it is found that acidic CO2RR is influenced not basically by composition variations in catalysts, substrates or electrolytes, but also by internal changes at the catalyst-electrolyte interface. Catalyst-electrolyte interface engineering involved electrolyte engineering, catalyst modification, and interface optimization provides many feasible solutions for acidic CO2RR to weaken HER competition. Importantly, it deepens the acidic CO2RR investigation to the exploration of catalyst electronic structures, interfacial adsorption of cations and anions, and the surface hydrophobicity in the presence electric fields. However, there are limited articles reviewing acidic CO2RR from this perspective, thus, this review aims to discussing the challenges, history, evaluation and breakthroughs of acidic CO2RR regarding catalyst-electrolyte interface engineering, providing insights for the future development of acidic CO2RR.