Study On Synthesis And Photocatalytic Activity Of Visible Light Responsive TiO₂Magnetivc Nano-Hollow Spheres

Semiconductor photocatalysis has become increasingly promising technology in the wastewater treatment because it is low-cost and completes the hazardous organic compound mineralization. Titanium dioxide (TiO2) photocatalysis has been the focus of the investigations, because of its high photocatalytic activity and its stability with respect to photocorrosion and chemical corrosion. Aiming at the disadvantages of TiO2powder, such as difficulty in separation, low using rate of transformation of photocatalytic technology, In order to solve these problems, visible light response magnetic photocatalysts are synthesized by sol-gel method.This dissertation includes three parts:1. Monodisperse NiFe2O4hollow nanospheres are synthesized via a facile solvothermal method. By using magnetic NiFe2O4hollow spheres as support, Using ammonium metavanadate as starting materials, Vanadium doped TiO2/SiO2/NiFe2O4hollow sphere were prepared by a sol-gel method. Vanadium doping restrains effectively the phase transformation from anatase to rutile. The absorption range and strength enhance evidently.Photocatalysts exhibit highly active photocatalytic performance when the degradation of Rhodamine B under visible light.2. By using magnetic NiFe2O4hollow spheres as support and SiO2as mesosphere, core-shell structure C,V-codoped TiO2/SiO2/NiFe2O4hollow microsphere are prepared by a sol-gel method. Its structure and morphology are characterized by means of XRD, SEM, TEM and UV-Vis. The results indicate that the C,V-TiO2/SiO2/NiFe2O4hollow microsphere are composed of SiO2mesosphere and anatase TiO2crust and the optimal calcined temperature of C,V-TiO2/SiO2/NiFe2O4is500℃.Camparing the sample without Carbon doping, C,V-TiO2/SiO2/NiFe2O4has higher catalytic activity.3.N and V-codoped TiO2/SiO2/NiFe2O4hollow nanospheres photocatalysts were prepared by a sol-gel process. The shape, structure size and properties of N and V-codoped TiO2/SiO2/NiFe2O4were investigated by XRD, TEM, SEM, UV-Vis spectra. The photocatalytic activities of the as-prepared magnetic catalysts were evaluated by the degradation of RhB at the room temperature under UV and visible light irradiation. Generally believed that the incorporated elemental nitrogen was acting as a photosensitizer [22]. The results show that1.0%V-containing co-doped TiO2hollow nanospheres photocatalysts had the highest activity under UV and visible light irradiation.Because a small amount of N atoms into the TiO2lattice, N will replace TiO2in the O party in the TiO2valence band to generate new levels of impurities, so narrow band gap is conducive to the absorption of visible light catalyst.