Electrolyte Effects on CO2 Electrochemical Reduction to CO

• DOI: 10.1021/acs.accounts.2c00080
• Publication Date: 2022-06-30T19:52:42Z
• Authors: Giulia Marcandalli; Mariana C. O. Mon...; Akansha Goyal; Marc T. M. Koper
• Keywords: Overpotential

ConspectusThe electrochemical reduction of CO2 (CO2RR) constitutes an alternative to fossil fuel-based technologies for the production fuels and commodity chemicals. Yet application CO2RR electrolyzers is hampered by low energy Faradaic efficiencies. Concomitant reactions, like hydrogen evolution (HER), lower selectivity, while conversion into (bi)carbonate through solution acid-base reactions induces additional concentration overpotential. During in aqueous media, local pH becomes more alkaline than bulk causing consumption homogeneous reactions. The latter effect, combination with solubility electrolytes (33 mM), leads a significant depletion at electrode surface.The nature electrolyte, terms cation identity, has recently emerged as important factor tune both efficiency. In this Account, we summarize recent advances understanding electrolyte effects on CO solutions, which first, crucial, step further reduced products. To compare literature findings meaningful way, focus results reported under well-defined mass transport conditions using online analytical techniques. discussion covers molecular-level proton donor, suppression gradient vs enhancement HER given rate cation, crucial enabling HER. These mechanistic insights are then translated possible implications industrially relevant cell geometries current densities.