A local Proton−Transport Promoter for Industrial CO2 Electroreduction to Multicarbon Products

Abstract

Industrial carbon dioxide electroreduction (eCO2RR) is of wide interests, also a great challenge to ensure sufficient and fast mass supply to achieve industrial-level current densities. Herein, a local proton-transport promoter has been developed by hybridizing Cu catalytic sites with proton hopping sites from dual-conductive polymers to tackle the mass-diffusion limit. The Cu/Polypyrrole exhibits extraordinary eCO2RR to C2+ performance with a high FEC2+ of 80.0% under an industrial current density of 700 mA/cm-2. Experimentally and theoretically, it is found protons transfer via a Grotthuss mechanism, whose conductivity is determined by the hydrogen bond formation and breakage (“-HN1---H N2H-” to “-HN1 H---N2H-”) at the hopping site from the dual-conductive Polypyrrole, rather than diffusion coefficient of the proton source and hydrous/anhydrous protons. Significantly, the advantageous proton transport of Cu/PPy is further confirmed by an in situ scanning electrochemical microscope testing, according to the proton change in the diffusion layer and local catalytic sites.