Solar energy-driven electrolysis with molecular catalysts for the reduction of carbon dioxide coupled with the oxidation of 5-hydroxymethylfurfural

Abstract

A paired electrolytic system was constructed with 4-(tert-butyl)phenoxy-decorated cobalt phthalocyanine (TBP-CoPc) and pyrene-tethered 2,2,6,6-tetramethylpiperidin-1-oxy (Py-TEMPO), which were non-covalently immobilized on carbon nanotubes to catalyze the CO₂ reduction to CO and the oxidation of biomass-derived 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA), respectively. Coupled electrolysis tests in a single electrolyzer with tri-electrode or di-electrode systems revealed that the potential change during electrolysis determined the product distribution, and a 96.9% FE for CO as well as 90.8% FE for FDCA was achieved with a cell voltage of 2.5 V in the di-electrode mode. More importantly, a sunlight-driven electrolytic system successfully drove this coupling reaction efficiently, paving the way for future developments in the production of high value-added chemicals with renewable energy sources.