Immobilized Tetraalkylammonium Cations Enable Metal-free CO 2 Electroreduction in Acid and Pure Water

• Published in: Angewandte Chemie International Edition Vol. 63; no. 9; p. e202317828
• Main Authors: Fan, Jia, Pan, Binbin, Wu, Jialing, Shao, Chaochen, Wen, Zhaoyu, Yan, Yuchen, Wang, Yuhang, Li, Yanguang
• Format: Journal Article
• Language: English
• Published: Germany 26.02.2024
• Subjects: Carbon Efficiency; Acidic Condition; Immobilized Cations; CO2 Electroreduction; Membrane Electrode Assembly
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202317828

Carbon dioxide reduction reaction (CO RR) provides an efficient pathway to convert CO into desirable products, yet its commercialization is greatly hindered by the huge energy cost due to CO loss and regeneration. Performing CO RR under acidic conditions containing alkali cations can potentially address the issue, but still causes (bi)carbonate deposition at high current densities, compromising product Faradaic efficiencies (FEs) in present-day acid-fed membrane electrode assemblies. Herein, we present a strategy using a positively charged polyelectrolyte-poly(diallyldimethylammonium) immobilized on graphene oxide via electrostatic interactions to displace alkali cations. This enables a FE of 85 %, a carbon efficiency of 93 %, and an energy efficiency (EE) of 35 % for CO at 100 mA cm on modified Ag catalysts in acid. In a pure-water-fed reactor, we obtained a 78 % CO FE with a 30 % EE at 100 mA cm at 40 °C. All the performance metrics are comparable to or even exceed those attained in the presence of alkali metal cations.