Rational Designing Microenvironment of Gas‐Diffusion Electrodes via Microgel‐Augmented CO2 Availability for High‐Rate and Selective CO2 Electroreduction to Ethylene

Abstract

Abstract Efficient electrochemical CO2 reduction reaction (CO2RR) requires advanced gas‐diffusion electrodes (GDEs) with tunned microenvironment to overcome low CO2 availability in the vicinity of catalyst layer. Herein, for the first time, pyridine‐containing microgels‐augmented CO2 availability is presented in Cu2O‐based GDE for high‐rate CO2 reduction to ethylene, owing to the presence of CO2‐phil microgels with amine moieties. Microgels as three‐dimensional polymer networks act as CO2 micro‐reservoirs to engineer the GDE microenvironment and boost local CO2 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 CO2 availability, and electrocatalytic CO2 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 CO2‐phil microgels for a higher rate of CO2RR‐to‐C2+, opening an avenue for several other microgels for more selective and efficient CO2 electrolysis.

Keywords

• CO2 micro‐reservoir
• electrochemical CO2 reduction reaction
• gas‐diffusion electrode
• GDE Microenvironment
• Pyridine Microgels