Anionic Surfactant-Tuned Interfacial Water Reactivity Promoting Electrocatalytic CO<sub>2</sub> Reduction
Wangxin Ge, Yihua Zhu, Haiyan Wang, Hongliang Jiang, Chunzhong Li
Abstract
The effects of the electrical double layer (EDL), which pertain to the compositions and interactions among electrolyte species, significantly impact the catalytic process. There is a pressing need to investigate the role of electrolyte components and to deepen our understanding of EDL effects. In this study, we tune the water activity within a range of anionic surfactants featuring different functional groups to adjust H 2 evolution activity and CO 2 reduction selectivity. We demonstrate that these anionic surfactants are active in the local reaction environment under a cathodic potential. The enhanced selectivity of CO 2 to CO can be attributed to the robust interfacial hydrogen-bonding network reformed by the anionic surfactants. This network diminishes the water dissociation activity and promotes the hydrogenation step in CO 2 reduction. Notably, the electrolyte incorporating anionic surfactants improves the CO 2 reduction performance, registering CO Faradaic efficiencies of 89.7% (RSO 3 –, SDS), 97.5% (RSO 4 –, SLS), 98.4% (RPO 4 2–, SMP), and 98.9% (RCOO –, SL) at −1.2 V versus RHE, thereby outperforming the blank KHCO 3 electrolyte (53.1%). This research underscores the crucial influence of anionic additives in the CO 2 RR.