Efficient photoreforming of biomass derived 5-(hydroxymethyl)furfural and simultaneous green hydrogen production by defective graphitic carbon nitride photocatalysts

Abstract

Using solar energy and water to convert biomass-derived 5-hydroxymethylfurfural (HMF) into valuable chemicals, while simultaneously producing green hydrogen, offers a promising recycling approach for a significant source of agricultural waste. Here, we report the design of a selective, stable and efficient HMF photocatalyst by the structural engineering of graphitic carbon nitride nanosheets. Our optimal few-layered nanosheet structure loaded with Pt clusters demonstrates high photocatalytic performance, achieving selective photooxidation of HMF to valuable 2,5-diformylfuran and 5-formyl-2-furancarboxylic acid, and the co-production of hydrogen at a high evolution rate of 75.52 ± 0.46 µmol g_cat⁻¹ h⁻¹, over 10 days of photoreforming. Density functional theory and comprehensive physicochemical characterisation reveal a synergistic effect of the Pt and carbon nitride surfaces, with the former enhancing water adsorption and dissociation and the latter providing a high density of COOH, –CO, and –COH adsorption sites for HMF. These insights into the optimal structuring of carbon nitride nanosheets provide a promising direction for the design of efficient photocatalysts for photoreforming with impact on various sustainable chemical recycling approaches.