Photocatalytic and photoelectrocatalytic conversion of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid: A review

The selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) represents a critical pathway for establishing sustainable, biomass-derived polymer value chains. While conventional conversion routes heavily rely on energy-intensive thermocatalysis, solar-driven approaches using photocatalysis and photoelectrocatalysis have emerged as compelling alternatives capable of operating under mild conditions. Moving beyond broad biomass valorization reviews, this article provides a dedicated evaluation specifically focused on photocatalytic and photoelectrocatalytic HMF-to-FDCA conversion systems. We critically assess recent advances in catalyst design and technological configurations, particularly highlighting their direct impacts on light utilization, charge carrier dynamics, and reaction efficiency. Furthermore, the underlying reaction pathways are systematically examined to clarify structure-performance relationships across photocatalytic and photoelectrochemical interfaces. Finally, this review addresses persistent bottlenecks, including limited photon utilization, rapid charge recombination, catalyst instability, and reactor scale-up, while outlining future strategies that connect material development with photoreactor design to advance economically viable solar-powered biorefineries.