Poly(ionic liquid) boosts overall performance of electrocatalytic reduction of low concentration of CO gas

Electrocatalytic reduction of CO (CORR) provides a feasible way for not only CO₂ conversion via tandem CO₂-to-CO-to-C₂₊ process but also CO utilization from industrial exhaust gases. In this work, poly(ionic liquid) modified Cu catalyst (Cu@PIL) was employed as the electrocatalyst to convert low concentration CO gas to high-value C₂₊ products. An over 90 % faradaic efficiency of C₂₊ products (FE_C2+) was obtained at a constant current density of 125.0 mA cm⁻² within a broad range of feedstock concentrations from 100.0 to 40.0 vol%. Remarkably, excellent comprehensive performance was achieved with feeding CO gas as less as 5.0 vol%, delivering a high FE_C2+ of 71.1 % with high CO conversion (67.4 %) and high energetic efficiency (29.1 %). Mechanistic studies suggest the local enrichment of CO via adsorption and accelerated mass transfer by porous PIL layer as well as the suppression of hydrogen evolution reaction enables the CO-to-C₂₊ transformation with diluted CO gas.