Molecular Co and Fe Catalysts for the Electrochemical and Photoelectrochemical CO2 Reduction with 2, 4, 6 and 8 Electrons

Abstract

Reduction of carbon dioxide has as main objective the production of useful organic compounds and fuels - renewable fuels - in which solar energy would be stored. Molecular catalysts can be employed to reach this goal. One route consists in first converting sunlight energy into electricity that could be further used to reduce CO2 electrochemically. Another approach is to directly use the visible photons and photo-stimulate the electrochemical reduction of the gas in the presence of an appropriate light absorbing material. Molecular catalysts may provide excellent selectivity. Hybrid systems in which a robust molecular catalyst is associated to a conductive or a semi-conductive support may combine the advantages of both homogeneous and heterogeneous catalysis.Using Co and Fe bio-inspired complexes (porphyrins, phthalocyanines and quaterpyridines), our recent results for CO, HCOOH, CH3OH and CH4 production at molecular cathodes [1-5] and photocathodes [6-8] will be discussed. We will illustrate the synergy between electrochemical and photochemical approaches and the rich potential of molecular catalysts to generate fuels from CO2 used as a renewable feedstock.