Highly selective conversion of 5-Hydroxymethylfurfural to 2,5-Diformylfuran with simultaneous H2 production over AuPd-modified tubular carbon nitride photocatalyst

AuPd-TCN enables photocatalytic 5-HMF oxidation coupled with H 2 evolution. • Achieving 69.2% DFF yield and 421.9 μmol·g⁻ 1 ·h⁻ 1 H 2 evolution rate within 2 h. • Revealing AuPd-TCN interfacial interactions to promote charge separation and transfer. • Confirming valence-band oxidation and conduction-band reduction coupling by DRIFTS and EPR. The selective oxidation of 5-hydroxymethylfurfural (5-HMF) to 2,5-diformylfuran (DFF) coupled with hydrogen (H 2 ) evolution offers a sustainable strategy for the high-value conversion of biomass-derived platform chemicals and clean energy production. In this study, tubular carbon nitride (TCN) is first prepared via self-assemble of a supramolecular precursor, followed by the loading of AuPd bimetallic nanoparticles on its surface through an impregnation-reduction method to construct the AuPd-TCN photocatalyst. Under visible-light irradiation for 2 h, AuPd-TCN delivers a DFF yield of 69.2% and a H 2 evolution rate of 421.9 μmol·g −1 ·h −1 , markedly outperforming pristine TCN (22.4%, 17.7 μmol·g −1 ·h −1 ), Au-TCN (39.8%, 204.2 μmol·g −1 ·h −1 ), and Pd-TCN (48.6%, 255.4 μmol·g −1 ·h −1 ). Structural and photoelectrochemical characterizations reveal that Au and Pd form bimetallic nanoparticles on TCN with strong interfacial electronic interactions that promote the separation and transfer of photogenerated charge carriers. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) confirms that the hydroxymethyl group of 5-HMF is selectively oxidized to an aldehyde group, while the furan ring skeleton remains intact during the reaction. Active species trapping experiments and electron paramagnetic resonance (EPR) analysis further demonstrate that photogenerated holes (h + ) and electrons (e - ) are the primary active species in this coupled reaction: h⁺ drives the selective oxidation of 5-HMF to DFF, while e - reduces H⁺ to H 2 on the AuPd bimetallic nanoparticles surface. This study provides an effective strategy for simultaneous biomass-derived chemical valorization and clean hydrogen production. Download: Download high-res image (147KB) Download: Download full-size image