Photodegradation of Toluene and Xylene by Fluidized Bed Gaseous System with TiO2/SiO2 Photocatalysts

A Review of Photocatalysts Prepared by Sol-Gel Method for VOCs Removal

“…It was believed that fluidized beds provide better use of light and better contact between the target compound and photocatalysts [52]. …”

“…This gap corresponds to 387 nm wavelength light and high recombination between electron-hole pairs. A number of works have focused on elevating the photocatalytic activity of TiO 2 , including studies involving doping with metals [ 57 , 71 ], doping with nonmetals [ 72 – 76 ], and coupling with other supports [ 50 , 52 , 66 – 68 , 77 – 87 ].…”

“…Another effective method for improving the photoactivity of TiO 2 is via coupling with other metal oxide materials and with semiconductor that have lower energy band gaps [ 84 ]. These materials include WO 3 [ 77 , 100 ], SiO 2 [ 52 , 66 , 67 , 77 , 79 , 81 , 87 , 101 ], CdS [ 78 ], YFeO 3 [ 68 ], or porous material with large surface areas (e.g., activated carbon) [ 50 , 82 , 83 , 86 ].…”

“…To increase the reaction rate of PCO in the gas-solid heterogeneous photocatalysis, it is necessary for the reaction system to provide efficient contact of excited photons with photocatalysts and gaseous reactants [ 52 ]. It was believed that fluidized beds provide better use of light and better contact between the target compound and photocatalysts [ 52 ].…”

“…It was reported that TiO 2 might be deactivated after a period of use [ 52 , 53 , 68 , 80 , 108 ], and that the intermediates and final products produced from photocatalytic oxidation, and which cover the catalytic surface, are responsible for TiO 2 ’s deactivation.…”