S, P modified CoFe-LDH derived CoFeS and CoFeP-400 catalysts efficiently catalyze the oxidation of HMF to FDCA

Abstract

In this study, cobalt–iron hydrotalcite-based catalysts doped with sulfur or phosphorus were developed for the selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA). Following the hydrothermal preparation of a CoFe-LDH precursor, CoFeS and CoFeP-400 catalysts were produced by either hydrothermal vulcanization with thioacetamide at 120 °C or phosphating with sodium hypophosphite at 400 °C. The catalysts were then characterized by XRD, HR-TEM, SEM, BET, XPS, N₂ physisorption and other techniques to explore their morphology, structure, chemical composition and physicochemical properties. Under optimized catalytic testing conditions (acetonitrile solvent, reaction temperature 120 °C, oxidant t-BuOOH, reaction time 12 h), CoFeS offered a HMF conversion of 100% and FDCA yield of 87.1%, whilst CoFeP-400 delivered a HMF conversion of 100% and FDCA yield of 89.5%. Both catalysts maintained high activity and FDCA selectivity over five cycles of HMF oxidation experiments.