A Highly Efficient Conjoined‐twin Porphyrin‐based Complex for the Electrochemical Reduction of CO to Ethanol

Abstract

AbstractElectrochemical conversion of carbon monoxide, a major one‐carbon product of carbon dioxide reduction, into high‐value multi‐carbon products is one of the promising strategies to address the overall energy demands and climate change. A lot of efforts have been devoted to the exploration of highly efficient catalysts for the formation of single carbon products. However, further reduction to more reduced products is hampered by high energy barriers for C−C bond formation and low selectivity of the products. Herein, the potential of homo‐bimetallic and hetero‐bimetallic complexes of previously established expanded twin porphyrin (H4L) ligand, also known as conjoined‐twin porphyrin (CTP) ligand, towards the reduction of CO to valued commodity chemicals is systematically investigated by using density functional theory (DFT) computations. In these complexes, the presence of two metal atoms in the N4 pockets enhances the chances of coupling of two adsorbed CO molecules, thus facilitating the formation of C−C bond formation. The results reveal that both the dicobalt and cobalt nickel complex of conjoined‐twin porphyrin ligand show high activity and selectivity towards the conversion of CO to ethanol with a limiting potential of only −0.59 V and −0.61 V, respectively. The narrow band gap and shallower d band centre could be attributed to the potential cause for the enhanced activity of Co containing complexes. Moreover, these complexes displayed high thermal stability, thus acts as potential candidates for experimental exploration. Our results offer a promising alternative to traditional Cu‐based electrocatalysts for the formation of C2 products.