Cascade electrosynthesis of glycolic acid from ethylene and oxygen with an energy efficiency of 62.9%

Abstract The high pollution and low purity associated with the conventional formaldehyde carbonylation process for glycolic acid (GA) production have motivated the search for alternative green pathway. Herein, we report a cascade conversion strategy integrating oxygen reduction reaction (ORR), ethylene oxidation, and ethylene glycol oxidation reaction (EGOR) for GA electrosynthesis. This approach achieves high energy efficiency at industrial current density levering generated hydrogen peroxide (H 2 O 2 ) as an oxidant. The Faraday efficiency (FE) of GA at whole scheme can reach 93.5% at 300 mA cm −2 . By replacing EG with ethylene and O 2 as raw materials, the ORR-ethylene oxidation-EGOR cascade conversion strategy shows improved energy conversation efficiency of 62.9% and significantly reduces its total outlay cost. Economic analysis reveals that the net profit of the cascade system reaches $26.8 million with a 30-year electrolyzer lifespan, which is 5.22 and 1.97 times higher than that of isolated ORR and EGOR systems.