Abstract
Efficient electrochemical CO(2) reduction reaction (CO(2)RR) requires advanced gas-diffusion electrodes (GDEs) with tunned microenvironment to overcome low CO(2) availability in the vicinity of catalyst layer. Herein, for the first time, pyridine-containing microgels-augmented CO(2) availability is presented in Cu(2)O-based GDE for high-rate CO(2) reduction to ethylene, owing to the presence of CO(2)-phil microgels with amine moieties. Microgels as three-dimensional polymer networks act as CO(2) micro-reservoirs to engineer the GDE microenvironment and boost local CO(2) availability. The superior ethylene production performance of the GDE modified by 4-vinyl pyridine microgels, as compared with the GDE with diethylaminoethyl methacrylate microgels, indicates the bifunctional effect of pyridine-based microgels to enhance CO(2) availability, and electrocatalytic CO(2) reduction. While the Faradaic efficiency (FE) of ethylene without microgels was capped at 43% at 300 mA cm(-2), GDE with the pyridine microgels showed 56% FE of ethylene at 700 mA cm(-2). A similar trend was observed in zero-gap design, and GDEs showed 58% FE of ethylene at -4.0 cell voltage (>350 mA cm(-2) current density), resulting in over 2-fold improvement in ethylene production. This study showcases the use of CO(2)-phil microgels for a higher rate of CO(2)RR-to-C(2+), opening an avenue for several other microgels for more selective and efficient CO(2) electrolysis.