Efficient conversion of 5-HMF to FDCA over MOF-on-MOF derived catalyst

Abstract

A template-assisted approach was employed to synthesize a MOF-on-MOF derived catalyst for the selective oxidation of 5-hydroxymethylfurfural (5-HMF) to produce 2,5-furandicarboxylic acid (FDCA). Characterization revealed that the catalyst forms a cobalt–manganese metal oxide composite phase with a hierarchical porous structure and uniformly distributed Co/Mn active sites. The oxygen vacancies work together with the Lewis acid sites to gradually oxidize the hydroxyl and aldehyde groups in 5-HMF. In the context of reaction conditions that have been identified as optimal (140 °C, 6 h, 50 mg catalyst, 5.88 mol L⁻¹ H₂O₂), the yield of FDCA was 87.55%, accompanied by 5-HMF conversion rate of 98.66%. The catalyst exhibited exceptional cycling stability, sustaining an FDCA yield exceeding 75% across five cycles. Mechanism studies indicate that the Co–Mn bimetallic synergistic effect optimizes the reaction pathway through electron transfer and oxygen species activation, while the microporous structure prolongs the residence time of intermediates through confinement effect, promoting multi-step oxidation. Compared with the single-metal MOFs derived catalysts, this catalyst has significantly improved adsorption performance and oxidation efficiency, providing an efficient solution for the green synthesis of the bio-based polyester monomer FDCA.