In Situ Spectroelectrochemical Study of Acetate Formation by CO2 Reduction Using Bi Catalyst in Amine-Based Capture Solution.

Abstract

Carbon capture and utilization (CCU) are technologies sought to reduce the level of CO₂ in the atmosphere. Industrial carbon capture is associated with energetic penalty, thus there is an opportunity to research alternatives. In this work, spectroelectrochemistry was used to analyze the electrochemical CO₂ reduction (eCO₂R) in CO₂ saturated monoethanolamine (MEA)-based capture solutions, in a novel CCU process. The in situ Fourier transform infrared (FTIR) spectroscopy experiments show that at the Bi catalyst, the active species involved in the eCO₂R is the dissolved CO₂ in solution, and not carbamate. In addition, the products of eCO₂R were evaluated under flow, using commercial Bi₂O₃ NP as catalyst. Formate and acetate were detected, with normalized FE for acetate up to 14.5 %, a remarkable result, considering the catalyst used. Acetate is formed either in the presence of cetrimonium bromide (CTAB) as surfactant or at higher current density (>-100 mA cm^-2) and the results enabled the proposition of a pathway for its production. This work sheds light on the complex reaction environment of a capture medium electrolyte and is thus relevant for an improved understanding of the conversion of CO₂ into value-added products and to evaluate the feasibility of a combined CCU approach.