Photocatalytic conversion of sodium lignosulfonate into vanillin using mesoporous TiO2 derived from MIL-125.

Mesoporous TiO 2 with regular pancake-like morphology was synthesized by facile calcination of MIL-125 (MIL = Materials of Institut Lavoisier) at different temperatures. The optimal sample MT400 (calcination at 400 °C) is composed of nanoparticles with a size of about 10 nm and mesopores of about 4–12 nm. Its specific surface area can reach up to 174 m2 g−1. In the photocatalytic conversion of sodium lignosulfonate, the yield of vanillin over MT400 is 2.1 mg/g, obviously superior to that over P25 TiO 2 (0.27 mg/g). MT400 with a large specific surface area offers sufficient active sites, and its mesoporous structure provides pathways for the transport of charge carriers and products, giving a satisfactory photocatalytic performance for vanillin generation. It is proved that h+ and ·O 2 − play the key role for vanillin generation from sodium lignosulfonate. This work indicates that MOF-derived metal oxides hold great promise in the application of biomass (photo)catalytic valorization. [Display omitted] • A pancake-like mesoporous TiO 2 was synthesized by the calcination of MIL-125. • MT400 is composed of particles with a size of ca. 10 nm and mesopores of 4–12 nm. • The yield of vanillin over MT400 is 7.7-fold higher than that of P25. • The structure is helpful to the transport of charge carriers, substrates and products. [ABSTRACT FROM AUTHOR]