Aerobic Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid over a Bi-Promoted Pt/Al2O3 Catalyst

2,5-furandicarboxylic acid (FDCA), a high-value biomass-derived monomer, serves as a crucial building block for sustainable polymers including polyesters, polyamides, and polyurethanes. This study systematically investigated the catalytic oxidation of 5-hydroxymethylfurfural (HMF) to FDCA over Pt/Al2O3and Pt–Bi/Al2O3catalysts. The 5Pt/Al2O3catalyst yielded 60.6% FDCA after 12 h under optimized conditions (80 °C, 0.1 MPa O2, 1 equiv. Na2CO3). Remarkably, Bi-modified 5Pt–1Bi/Al2O3catalyst dramatically enhanced catalytic performance, achieving 94.1% FDCA yield within 6 h under optimized conditions (80 °C, 1.5 MPa O2, 2 equiv. Na2CO3). Comprehensive characterization revealed that the exceptional activity originates from Bi–O–Pt interactions that modulate the electronic structure and oxidation state of Pt active sites, which facilitates the oxidation of intermediate 5-formyl-2-furancarboxylic acid (FFCA) to FDCA, the rate-limiting step of HMF oxidation. This work demonstrates an efficient Bi-promoted Pt catalytic system for FDCA production with significant potential for industrial application.