Boosting the Efficiency\nand Selectivity of Electrocatalytic\nReduction of CO<sub>2</sub> to C1 Products by Mn-Porphyrin via Axial\nLigation

The urgency to address climate change hinges on developing\nefficient,\nselective, low-cost, and durable catalysts for effective CO<sub>2</sub> reduction, enabling the conversion of greenhouse gases into valuable\nresources. This study evaluates the performance of manganese porphyrin\n(MnPr) and its tailored derivatives that are designed by its axial\nligation with imidazole, carbene, and pyridine groups (MnPr-Im, MnPr-NHC,\nand MnPr-Py) for the electrocatalytic reduction of CO<sub>2</sub> into\nvalue-added chemicals. The energetics and mechanism of the CO<sub>2</sub> reduction reaction (CO<sub>2</sub>RR) have been explored\nusing the density functional theory-based computational approach.\nThe goal is to devise strategies that improve the CO<sub>2</sub>RR\nefficiency while minimizing the competing hydrogen evolution reaction\n(HER). The primary reduction product is HCOOH, and the minimum overpotential\n(η<sup>HCOOH</sup>) values to lead to this product are 0.22,\n0.45, 0.82, and 0.12 V on MnPr, MnPr-Im, MnPr-NHC, and MnPr-Py, respectively.\nIn particular, electrocatalysis by MnPr-Py (η<sup>HCOOH</sup> = 0.12 V) surpasses the catalytic activity of the state-of-the-art\nmetal surfaces Pt(111) (η = 0.46 V) and Cu(211) (η = 0.77\nV). The in-depth analysis of energy profiles, scaling relationships,\nelectrode potentials, and pH provides a rationalization of the excellent\nreactivity and selectivity of the designed catalysts for the CO<sub>2</sub>RR over the competing HER. The study provides conclusive evidence\nthat axial ligation of MnPr provides a highly efficient electrocatalyst\nthat exhibits the advantage of excellent product selectivity, high\nactivity, and minimum overpotential, prompting further experimental\ninvestigations in this direction.