Mauricio Portiolli Franco

• Franco, Mauricio Portiolli; Garcia, Gabriela; Braga, Ataualpa Albert Carmo & Flores, Ainara Nova (2026). COMPUTATIONAL INSIGHTS INTO CO2 TO ACETATE VIA MANGANESE- CORROLE ELECTROCATALYSIS. doi: https:/iccc2026.com/. Fulltekst i vitenarkiv Vis sammendrag

  The electrocatalytic reduction of CO2 into value-added C2 products, such as acetate, represents a promising strategy for carbon capture and utilization aligned with global sustainability goals. However, achieving high selectivity and efficiency remains challenging due to the thermodynamic stability of CO2 and the mechanistic complexity associated with C–C bond formation. A notable example is a manganese–corrole complex immobilized on carbon paper, which has been reported to produce acetate as the major product at potentials more positive than −1.50 V vs. Fc/Fc+, together with methanol and CO. At −1.65 V vs. Fc/Fc+, however, molecular hydrogen replaces CO in the product distribution. Based on the experimental reports,1 the proposed mechanism involves C–C coupling via CO₂ addition to a metallocarboxylic acid intermediate (Mn– COOH), forming the hydrogen oxalate anion (HC2O4-), which is then further reduced to acetate. In this work, we present a DFT investigation of the mechanism for the CO2 electroreduction to C1 and C2 products. Calculations were performed using the PBE/def2-TZVP//B3LYP/def2-SVP level of theory, including D3BJ and SMD(AcCN). Since catalysis is experimentally observed only in the presence of both CO2 and H2O, the proton source was modeled as H2CO3. Redox potentials were computed using isodesmic reactions referenced to the calculated Fc/Fc⁺ redox couple. The results reveal a sequence of Mn–CO and Mn–CHO intermediates in which the initial formation of the Mn–CO adduct is thermodynamically accessible, while subsequent protonation and C– O bond activation steps display moderate barriers that are sensitive to the applied potential. A Comparison of the relative stabilities of Mn–CO versus more reduced Mn– C species clarifies why CO emerges as a product within a specific potential window, and why further reduction toward fully hydrogenated products is disfavored.

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