Photocatalytic Oxidation of HMF under Solar Irradiation: Coupling of Microemulsion and Lyophilization to Obtain Innovative TiO2-Based Materials

• Published in: Molecules (Basel, Switzerland) Vol. 25; no. 22; p. 5225
• Main Authors: Allegri, Alessandro, Maslova, Valeriia, Blosi, Magda, Costa, Anna Luisa, Ortelli, Simona, Basile, Francesco, Albonetti, Stefania
• Format: Journal Article
• Language: English
• Published: MDPI 10.11.2020; MDPI AG
• Subjects: 5-hydroxymethyl furfural; microemulsion; photocatalysis; spray-freeze drying; TiO2
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules25225225

The photocatalytic oxidation of biomass-derived building blocks such as 5-hydroxymethylfurfural (HMF) is a promising reaction for obtaining valuable chemicals and the efficient long-term storage of solar radiation. In this work, we developed innovative TiO2-based materials capable of base-free HMF photo-oxidation in water using simulated solar irradiation. The materials were prepared by combining microemulsion and spray-freeze drying (SFD), resulting in highly porous systems with a large surface area. The effect of titania/silica composition and the presence of gold-copper alloy nanoparticles on the properties of materials as well as photocatalytic performance were evaluated. Among the lab-synthesized photocatalysts, Ti15Si85 SFD and Au3Cu1/Ti15Si85 SFD achieved the higher conversions, while the best selectivity was observed for Au3Cu1/Ti15Si85 SFD. The tests with radical scavengers for both TiO2-m and Au3Cu1/Ti15Si85 SFD suggested that primary species responsible for the selective photo-oxidation of HMF are photo-generated electrons and/or superoxide radicals.