Hierarchical ZSM-5/SBA-15 composites supported non-Noble metal oxides for efficient catalytic oxidation of HMF to FDCA

Abstract

BACKGROUND

The efficient utilization of biomass resources is a key pathway to replace fossil fuels. The oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) played an important role for synthesizing bio-based polyester monomers. In this study, a series of ZSM-5/SBA-15 composite molecular sieves were prepared via the simple mechanical grinding method to construct micro-mesoporous supports with pore size of 0.64 ~ 9.31 nm, hierarchical structure, and dual acidic sites. Then, non-noble metal oxides (Co, Fe, Cr, and Mn) were loaded on composite supports by wet impregnation method, respectively. The composite support ZS-21 optimized the dispersion and stability of the active component, accelerated mass transfer, and thereby universally enhanced the catalytic activity of non-noble metal oxides.

RESULTS

The most pronounced improvement was observed for Cr-ZS-21, which achieved a 77% increase of FDCA yield compared with that of single supports. Meanwhile, 10Co-ZS-21 catalyst showed the best performance with HMF conversion of 96.6% and FDCA yield of 55.1% under optimized conditions (140 °C, 1.0 MPa O₂, 24 h), and FDCA yield remained at 52.98% after five cycles. Based on the catalyst characterization, we considered that the coexisting Co³⁺ and Co²⁺ established a dynamic redox cycle, providing the sustained driving force for the stepwise oxidation. The stable Co-O-Si chemical bonds and the hierarchical pore structure collectively enhanced the catalytic activity and stability.

CONCLUSION

This study provided a series of non-noble metal catalysts by a facile synthesis method for the efficient production of bio-based FDCA, which possessed cost advantages and industrial potential. © 2026 Society of Chemical Industry (SCI).