Modulated local electron-proton match for industrial-level electrocatalytic CO2 reduction to multicarbon products

Matched, oriented and fast local proton and electron supply are vital for industrial-level eCO 2 RR. • Modifying Cu catalysts using conductive functionalized polymers, could finely modulate proton and electron transport. • Methyl groups repel water and confine CO 2 , *CO intermediates nearby Cu, suppress HER and augment carbon-carbon coupling. A b s t r a c t Electrocatalytic CO 2 reduction reaction (eCO 2 RR) is an effective solution for environmental and energy crises caused by excessive CO 2 emission, consisting of multiple proton-coupled electron transfer (PCET) steps. Especially, to achieve industrial-level current densities, oriented and fast proton and electron supply is critical while challenging due to hydrogen evolution by-reaction (by-HER). In this work, functionalized conductive polymers are utilized to modify the traditional Cu-based gas diffusion electrode (GDE) regulating both local electron and proton transport for eCO 2 RR. Among which, pyrrole-3-methyl (PPy-3-CH 3 ) modified Cu-GDE has achieved an excellent Faradaic efficiency for double-carbon (C 2 ) products above 80.0% in a wide working range of 300–600 mA cm −2 , due to its moderate activation energy barrier for electron and proton conduction. Specifically, the electron and proton transport via the facile Grotthuss mechanism, whose energy barriers are lower than the Vehicle mechanism. Furthermore, -CH 3 groups could repel water, confine CO 2 reactants and *CO intermediates nearby Cu catalytic sites, suppressing by-HER and augmenting carbon-carbon coupling. However, -COOH groups also act as proton hopping sites except -NH groups, increasing local protons and thus severe by-HER. This work underscores importance of matched local electron-proton supply for electrocatalysts during PCET mediated electrocatalytic reaction, facilitating their industrial success. Download: Download high-res image (247KB) Download: Download full-size image Fast, oriented and matched proton and electron supply is developed by modifying the cupper based electrocatalyst using conductive polymers with different functional groups at various positions, therefore, achieving an industrial-level process of electrochemical CO 2 reduction to multi-carbon products.