Amino-Functionalization Enhanced CO2 Reduction Reaction in Pure Water

Abstract

The electrochemical reduction of carbon dioxide (CO 2 RR) to carbon monoxide 11 represents a cost-effective pathway towards realizing carbon neutrality. To suppress 12 the hydrogen evolution reaction (HER), the presence of alkali cations is critical, 13 however which can lead to precipitate formation on the electrode, adversely impacting 14 device stability. Employing pure water as the electrolyte in zero-gap CO 2 electrolyzers 15 can address this challenge, albeit at the cost of diminished catalyst performance due to 16 the absence of alkali cations. In this study, we introduce a novel approach by 17 implementing amino modifications on the catalyst surface to mimic the function of 18 alkali metal cations, while simultaneously can work in pure water. This modification 19 enhances the adsorption of carbon dioxide and protons, thereby facilitating CO 2 RR 20 while concurrently suppressing HER. Utilizing this strategy in a zero-gap CO 2 21 electrolyzer with pure water as the anolyte resulted in an impressive carbon monoxide 22 Faradaic efficiency (FE CO ) of 95.5% at a current density of 250 mA·cm -2 , while 23 maintaining stability for over 180 hours without any maintenance.