Gas diffusion in catalyst layer of flow cell for CO2 electroreduction toward C2+ products

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.