Preparation Of Titanium-based Photocatalytic Materials And Their Properties

Semiconductor photocatalysis has attracted a wide attention for its outstanding performance on environmental purification.Because the traditional TiO₂ photocatalyst has low quantum efficiency and can not utilize visible light,modification of TiO₂ or development of new photocatalytic materials has been a research focus in photocatalytic field. Device of photocatalyst to achieve recovery and continuous operation is another research hotspot in recent years.Therefore,this work focuses on the controllable preparation and device of photocatalyst.The main innovative research findings and conclusions include:1.According to the characteristics of layered double hydroxides (LDHs) with the homogeneous dispersion of metal elements in atomic scale and in-situ transformation to spinel-type composite metal oxide at high temperature,a NiTiO₃-based UV-visible light photocatalyst was prepared using Ni-Ti LDH as precursors after calcination at high temperature.Photoabsorption properties show the UV-light activity originating from the synergistic contribution of wide band gap semiconductors while the visible light absorption arises from NiTiO₃ nanoparticles.Methylene blue can be degraded over the NiTiO₃ composite catalysts under both UV and visible light irradiation.Under UV irradiation, methylene blue can be further mineralized.The activity was enhanced with the rise in the content of NiTiO₃.2.According to the characteristics of LDHs with the cation avoidance rule and the topotatic transformation to bimetal oxide at low temperature,a NiO-sensitized TiO₂ visible light photocatalyst with shared lattice oxygens was prepared using Ni-Ti LDH as precursors after calcination at low temperature.The interfacial Ti-O-Ni linkages act as an efficient electron transfer conduits to achieve photosensitization.The combination of NiO-sensitizing and N-doping further enhances the photocatalytic activity. The photocatalytic activity remained unchanged after being recycled for eight times.3.According to the characteristics of high light utilization for nozzle surface of TiO₂ nanotube array,ZnO and WO₃ were used to modify of the nozzle surface to enhance the quantum efficiency of TiO₂.After modification by ZnO and WO₃,the photoconversion efficiency are 2.8 and 4.4 times,the photocatalytic reaction rate are 1.5 and 1.8 times,the photoelectrocatalytic reaction rate 1.9 and 2.2 times than TiO₂ nanotube array.4.According to the characteristics of low light utilization for inner surface of TiO₂ nanotube array,introduction of a-FeOOH into the tube, using the H₂O₂ originated from TiO₂ photocatalytic process to achieve coupling of photocatalytic-Fenton reaction.Studies have proved that the photocatalytic and photoelectrocatalytic reaction rate are 1.8 and 3.4 times than TiO₂ nanotube array.