In this work, 12-tungstophosphoric acid-TiO 2 composite (PTA-TiO 2 ) catalysts were fabricated by a simple method of impregnation-heat treatment. PTA-TiO 2 composites were characterized by XRD , XPS, TG/DSC, FTIR , UV−vis diffuse reflectance spectra and N 2 adsorption–desorption measurements. The results showed that the heat treatment temperature (200–500 °C) significantly affected the composition and structure of the composite. The higher calcination temperature could destroy the Keggin structure of PTA. The PTA-TiO 2 catalyzed oxidation of cyclohexene by H 2 O 2 to adipic acid demonstrated that the Keggin structure of PTA was critical to the catalytic activity of PTA-TiO 2 . Furthermore, under the photo-thermal catalytic condition, the reaction system showed higher cyclohexene conversion and adipic acid yield. A synergistic effect between the photo- and thermal approach was noticed in the PTA-TiO 2 catalyst prepared at 200 °C (PTA-TiO 2 (200)). Based on the experimental data, a thermocatalysis-dominated but photocatalysis-promoted mechanism was proposed to explain the improvement in catalytic efficiency. The catalyzed oxidation of cyclohexene with photo-thermal synergy enables utilization of sunlight and offers a novel perspective for the manufacture of adipic acid.
H 3 PW 12 O 40 /TiO 2 (abbreviated PW 12 /TiO 2 ) nanofibers catalysts have been successfully prepared via calcinating off the respective electrospun PVP/[PW 12 + Ti(OC 4 H 9 ) 4 ] composite nanofibers for the first time and they show ultra-deep desulfurization catalytic performance in mild conditions. PW 12 /TiO 2 nanofibers consist of anatase phase TiO 2 and Keggin structure PW 12 , the diameter of which is approximately 100 nm. Compared with PW 12 /TiO 2 nanoparticles, 40 wt.% PW 12 /TiO 2 nanofibers (the weight percentage of PW 12 loading on TiO 2 nanofibers was 40%) exhibited the higher catalytic activity under the same conditions. DBT could be removed completely within 30 min at 70 °C using 0.02 g 40 wt.% PW 12 /TiO 2 nanofibers as catalysts, when ionic liquid (IL) [Bmim]PF 6 was as extraction agent. Additionally, sulfur removal of different substrates decreased in the following orders: DBT > BT > 4,6-DMDBT under the same conditions. Even after 5-times recycling, the catalytic activity of 40 wt.% PW 12 /TiO 2 nanofibers was not significant decreased. As a total result, these novel PW 12 /TiO 2 nanofibers can be used to deeply desulfurize in the industry.
危险品化学品经营许可证（带存储）