Multiple C-C bond formation upon electrocatalytic reduction of CO2 by a molecular catalyst

Abstract

Molecular macrocycles show very promising electrocatalytic properties for the reduction of carbon dioxide. Up to now, only C1 products were produced by these catalysts. We show here that iron phthalocyanine, a commercially available molecule based on earth abundant elements, can produce light hydrocarbons upon electrocatalytic reduction of CO2 in aqueous conditions and neutral pH. When an electrochemical potential of -0.7 to -1.1 V vs. RHE is applied to a glassy carbon electrode modified with iron phthalocyanine, carbon monoxide is generated as main product. An increasing fraction of hydrogen is observed as the potential is decreased and small amounts of C1 to C4 saturated and unsaturated products are evolved. Control experiments in the absence of CO2 or catalyst does not produce any of these compounds. X-ray spectroscopic analysis of the electrode during catalysis show that the molecular catalyst remains intact and is responsible from the reaction.

Mechanism of CO2 Electroreduction to Multicarbon Products over Iron Phthalocyanine Single-Atom Catalysts

“…This results in the reduction of CO 2 over PcFe­(“-I”) being more likely than bicarbonate reduction (Figure S4). As reported in the recent study by our group, in a control experiment with Ar-saturated 0.1 M KHCO 3 at pH ≈ 8.5 (without purging any CO 2 gas), we only observed an extremely faint signal of CO, C 2+ over PcFe. Since there is almost no CO 2 in this experimental condition, the trace amount of carbon products is likely the result of bicarbonate reduction.…”