Utilization of CO₂ for Electrocarboxylation of Benzophenone Using MXene-Based Electrodes: A Sustainable Approach

The significant rise in atmospheric carbon dioxide (CO2) levels has prompted the need to develop efficient methods for CO2 conversion and fixation methods. Electrocarboxylation reaction is a highly efficient and sustainable method for activating and utilizing CO2, yielding essential carboxylic acids and their analogues, which are important intermediates in the pharmaceutical and fuel industries. This research demonstrates the efficiency of 2D Ti3C2Tx and Ta2CTx MXene-modified carbon fiber paper electrodes (Ti3C2Tx/CFP and Ta2CTx/CFP) for CO2 fixation with benzophenone in a tetrabutylammonium bromide/acetonitrile (TBABr/CH3CN) medium, yielding benzilic acid. Ti3C2Tx/CFP exhibited superior electrocatalytic activity with a lower reduction potential for benzophenone at −1.0 V and achieved a 72% yield of benzilic acid at an optimum current density of 50 mA cm–2. In comparison, Ta2CTx/CFP exhibited a cathodic peak at −1.08 V, producing a 66% yield at 70 mA cm–2. The electron paramagnetic resonance spectrum substantiates the generation of reactive radical intermediates during the reaction. Ti3C2Tx/CFP showed robust structural stability with ∼88% Faradaic efficiency and a turnover frequency of 1.90444 × 10–5 s–1, indicating its potential for CO2 fixation.