Confined molecular catalysts provide an alternative interpretation to the electrochemically reversible demetallation of copper complexes
Etienne Boutin, Aude Salamé, Marc Robert
Abstract
etal phthalocyanines and porphyrins are among the most popular molecular catalysts for the electrochemical reduction of CO 2 . Recently, some copperbased complexes from these ligand families have been reported to promote the formation of methane and even ethylene at a high rate, an unprecedented property for a molecular catalyst 1 . More recently, operando X-ray Absorption Spectroscopy studies revealed that under cathodic conditions, small copper nanoparticles were forming from complex demetallation and were responsible for the catalysis 2 . The same studies claimed that the molecular Cu complexes are electrochemically reassembled when the electrode potential goes back to anodic value. Herein, we bring a different interpretation to the latter point, in accordance with all experimental data provided in the original article. Our interpretation accounts for the presence of electrochemically inert metal complexes confined inside the catalytic film and calls for a reassessment of some well-established views.