Investigation of m- and p-xylene linked bimetallic Ni-cyclam-complexes as potential electrocatalysts for the CO2 reduction

Abstract

Among the various molecular CO₂ reduction catalysts, the [Ni(cyclam)]²⁺ (Ni-{N₄}) complex with its earth-abundant metal center and macrocyclic ligand proved to be efficient for the selective electrochemical conversion of CO₂ to CO. In the present study we now connected the two Ni-cyclam units by using para- and meta-xylene as organic linkers attached to the amines of the macrocycle to form the p-{Ni₂} and m-{Ni₂} complexes, respectively, and test them as catalysts for the electrochemical CO₂ reduction reactions. Notably, the p-{Ni₂} complex demonstrates a higher faraday efficiency in the electrochemical reduction of CO₂ to CO compared to the m-{Ni₂} complex. This finding highlights the significant role played by the M-M distance in influencing this catalytic process.