The present invention relates to the use of complexes of water soluble porphyrins of formula (I) below wherein R1 to R10 and R1' to R10' are as defined in claim 1, with iron as catalysts for the selective electrochemical reduction of CO2 into CO, electrochemical cells comprising them, and methods for reducing electrochemically CO2 into CO using said complexes, or said electrochemical cells, thereby producing CO or syngas, in water as the solvent.