Oxidation of 2,5-bis(hydroxymethyl)furan to 2,5-furandicarboxylic acid with morphology-dependent Au/CeO2 catalysts

Abstract

2,5-Furandicarboxylic acid (FDCA), a bio-based diacid with a rigid ring, has a similar structure to petroleum-based terephthalic acid. Its co-polyester with ethylene glycol has excellent performance in terms of thermal and mechanical properties. Herein, an Au/CeO₂-rod catalyst with rich oxygen vacancies was developed to achieve the efficient oxidation of 2,5-bis(hydroxymethyl)furan (BHMF) to FDCA with a 92 % yield under mild conditions, with the addition of 4 equivalents of Na₂CO₃ at 80℃ under 2 MPa O₂ for 6 h. The large specific surface area of CeO₂-rod is beneficial for better dispersion of Au nanoparticles. Meanwhile, the high activity of Au/CeO₂-rod can be attributed to that the rod-shaped CeO₂ exposed more active (100) facets, resulting in strong metal-support interaction between Au nanoparticles and CeO₂-rod. This could generate more Au species with oxidized state and more oxygen vacancies, thus promoting the reactant adsorption and oxygen activation and enhancing the final oxidation activity. The oxidation of 5-hydroxymethyl-2-furancarboxylic acid to FDCA was determined as the rate-determining step in the oxidation of BHMF over the Au/CeO₂ catalyst.