Photocatalytic and hydrothermal transformation of glucose with commercial TiO2 catalysts for a hybrid valorization process.

SSCI-VIDE+CARE:CDFA+IBD:FDA:MET:CGU:NESInternational audiencePhotocatalytic and hydrothermal catalytic conversion of glucose in aqueous solutions were studied with the objective of subsequently combining them to decrease energy expenditure and limit side products formation. The photocatalytic process (UV: 365 nm, 6.7 mW/cm², air) involved UV100, PC105, MPT-625, Rut 160, P25 and P90. It allowed the formation of formic acid, glyceraldehydes (GAL), gluconic acid (GA), erythrose (ER), arabinose, and lactic acid (LA). P25 and P90 were selective for GA and ER. MPT-625 and Rut160 were selective for GAL.The hydrothermal process (120°C) using the above catalysts allowed the formation of mainly fructose with UV100, PC105, P25 and P90; and hydroxymethylfurfural with MPT-625 and Rut160. The catalytic performances under air and argon were similar.The search for potential relationships between the acid-base properties of the catalysts and their activity was investigated using the model reaction of dihydroxyacetone conversion in water which showed that MPT-625 and Rut 160 did not promote LA formation due to absence of Lewis acid sites, P25 and P90 might have more of such sites than UV100 and PC105. The adsorption of pyridine monitored by FTIR test showed that Rut160 had the least Lewis acid sites and had BrØnsted acid sites