Characterization and performance of carbon supported platinum-bismuth bimetallic catalysts tested in 5-hydroxymethylfurfural aerobic oxidation to 2,5-furandicarboxylic acid

The increasing demand for sustainable alternatives to petroleum-based chemicals has driven research towards the utilization of renewable feedstock, such as lignocellulosic biomass (LCB), to produce high-value products. Among LCB-derived platform molecules, 5-hydroxymethylfurfural (HMF) has become a key building block for bio-based monomers such as 2,5-furandicarboxylic acid (FDCA), among many others. This study reports the successful synthesis of various Pt-Bi catalysts supported on activated carbon (C) and investigates their role in the HMF conversion to FDCA.

The catalytic performance of the Pt-Bi/C catalysts was evaluated in batch reactors, using HMF in an aqueous reaction medium, with 1 M of Na₂CO₃ to provide alkalinity, and under 10 bar of O₂. These results demonstrated a strong correlation between catalyst properties and their catalytic activity. Among the prepared catalysts, the 9Pt-3Bi/C catalyst was the most efficient one, achieving a yield to FDCA of 99.7 %. Further investigations revealed that the 9Pt-3Bi/C catalyst maintained its excellent performance even under reduced reaction times, lower temperatures, and reduced catalyst loadings, demonstrating its potential for practical applications.

Across all reactions, it was observed that, under the tested reactions conditions, the existence of side reactions involving HMF degradation to other compounds was significant. This underscores the challenge of achieving quantitative HMF conversion to FDCA, enhancing the importance of catalyst properties and reaction conditions optimization to minimize by-product formation.