Gas diffusion in catalyst layer of flow cell for CO2 electroreduction toward C2+ products
Xiqing Wang, Qin Chen, Yajiao Zhou, Yao Tan, Ye Wang, Hongmei Li, Yu Chen, Mahmoud Sayed, Ramadan A. Geioushy, Nageh K. Allam, Junwei Fu, Yifei Sun, Min Liu
Abstract
The use of gas diffusion electrode (GDE) based flow cell can realize industrial-scale CO2 reduction reactions (CO2RRs). Controlling local CO2 and CO intermediate diffusion plays a key role in CO2RR toward multi-carbon (C2+) products. In this work, local CO2 and CO intermediate diffusion through the catalyst layer (CL) was investigated for improving CO2RR toward C2+ products. The gas permeability tests and finite element simulation results indicated CL can balance the CO2 gas diffusion and residence time of the CO intermediate, leading to a sufficient CO concentration with a suitable CO2/H2O supply for high C2+ products. As a result, an excellent selectivity of C2+ products ~ 79% at a high current density of 400 mA·cm−2 could be obtained on the optimal 500 nm Cu CL (Cu500). This work provides a new insight into the optimization of CO2/H2O supply and local CO concentration by controlling CL for C2+ products in CO2RR flow cell.