Multiple C–C bond formation upon electrocatalytic reduction of CO(2) by an iron-based molecular macrocycle

Molecular macrocycles are very promising electrocatalysts for the reduction of carbon dioxide into value-added chemicals. Up to now, most of these catalysts produced only C(1) products. We report here that iron phthalocyanine, a commercially available molecule based on earth-abundant elements, can produce light hydrocarbons upon electrocatalytic reduction of CO(2) in aqueous conditions and neutral pH. Under applied electrochemical potential, C(1) to C(4) saturated and unsaturated products are evolved. Isotopic labelling experiments unambiguously show that these products stem from CO(2). Control experiments and in situ X-ray spectroscopic analysis show that the molecular catalyst remains intact during catalysis and is responsible for the reaction. On the basis of experiments with alternate substrates, a mechanism is proposed for the C–C bond formation step.