LAUSR

Electroreduction of carbon dioxide (CO2RR) into CO is one of the simplest ways to valorize CO2 as a source of carbon. Here we report an original, cheap and robust, Cu-based hybrid catalytic material, consisting of a polymer of Cu phtalocyanine coated on carbon nanotubes (CNTs), which proved selective for CO production (Faradic yield 80%) at relatively low overpotentials. Polymerisation of Cu phtalocyanine here is shown to have a drastic effect on the selectivity of the reaction since molecular Cu phtalocyanine is instead selective for proton reduction under the same conditions. Finally, while the material only displays isolated Cu sites, within a phtalocyanine-like CuN4 coordination, in situ and operando X-ray absorption spectroscopy show that the Cu atoms fully convert, under operating conditions, into Cu nanoparticles, which are likely to be the catalytic species. Interestingly this restructuration of the metal sites is reversible.