NiFe-LDH/BiVO₄–BOD Photocatalytic Fuel Cell for Bias-Free and Selective 5-Hydroxymethylfurfural Oxidation to 2,5-Furandicarboxylic Acid

The efficient conversion of renewable biomass into value-added products is essential for sustainable development. In this work, we report a two-chamber photocatalytic fuel cell (PFC) consisting of a NiFe-LDH/BiVO₄/FTO photoanode and a BOD/TCPP/BP/ITO biocathode, which allows for the simultaneous accomplishment of energy conversion and bias-free production of 2,5-furandicarboxylic acid (FDCA). After optimization, the PFC achieves a maximum power density of 859.0 ± 3.0 μW cm^-2 at 0.52 V. TEMPO-mediated 5-hydroxymethylfurfural (HMF) oxidation occurs spontaneously within the PFC upon illumination due to the potential difference between the photoanode and biocathode, effectively and selectively converting HMF to FDCA with a yield (%) and Faradaic efficiency of approximately 100%, and possesses good durability after six cycles (30 h) of FDCA production (retaining 90.8% of its initial value). Therefore, the proposed PFC offers a promising solution to the challenges associated with the conversion of renewable biomass.