Enabling Efficient Aerobic 5-Hydroxymethylfurfural Oxidation to 2,5-Furandicarboxylic Acid in Water by Interfacial Engineering Reinforced Cu-Mn Oxides Hollow Nanofiber.

Abstract

Herein, a one-dimensional hollow nanofiber catalyst composed of tightly packed multiphase metal oxides of Mn2 O3 and Cu1.4 Mn1.6 O4 was constructed by electrospinning and tailored thermal treatment procedure. The characterization results comprehensively confirmed the special morphology and composition of various comparative catalysts. This strategy endowed the catalyst with abundant interfacial characteristics of components Mn2 O3 and Cu1.4 Mn1.6 O4 nanocrystal. Impressively, the tuning thermal treatment resulted in tailored CuI sites and surface oxygen species of the catalyst, thus affording optimized oxygen vacancies for reinforced oxygen adsorption, while the concomitant enhanced lattice oxygen activity in the constructed composite catalyst ensured the higher catalytic oxidation ability. More importantly, the regulated proportion of oxygen vacancy and lattice oxygen in the composite catalyst was obtained in the best catalyst, beneficial to accelerate the reaction cycle. Compared to other counterparts obtained by different temperatures, the CMO-500 sample exhibited superior selective aerobic 5-hydroxymethylfurfural (HMF) oxidation to 2,5-furandicarboxylic acid (FDCA, 96 % yield) in alkali-bearing aqueous solution using O2 at 120 °C, which resulted from the above-mentioned composition optimization and interfacial engineering reinforced surface oxygen consumption and regeneration cycle. The reaction mechanism was further proposed to uncover the lattice oxygen and oxygen vacancy participating HMF conversion process.