Ultrasonic Spray Pyrolysis Synthesis Of Solid Solution Photocatalysts And Their Photocatalytic Properties

Since Fujishama and Honda discovered that hydrogen can be generated from water by TiO₂ electrode in 1972,many efforts have been made to improve the photocatalytic performance of TiO₂.Because of its high photostability,nontoxicity,low cost,and availability,TiO₂ has been widely utilized for photocatalytic decomposition of harmful organic compounds in water and air.However,it can not utilize the solar light efficiently due to its large band gap(3.2eV).In order to enhance the quantum efficiency of TiO₂, many investigations have been made to improve the intrinsic efficiency of TiO₂.These include doping by transition metal elements,nonmetal elements,sensitization,coupling with other semiconductors,and addition of noble metals.In this thesis,a series of Ti_1-xZr_xO₂ solid solutions photocatalysts(x=0.000,0.045, 0.090,0.135,and 0.180)were directly obtained by an ultrasonic spray pyrolysis method (USP).The resulting samples were characterized by X-ray diffraction,scanning electron microscopy,transmission electron microscopy,nitrogen adsorption,and UV-Vis diffuse reflectance spectroscopy.The characterizations revealed core-shell spherical structures of the resulting solid solutions.We evaluated photocatalytic activities of the solid solutions on degradation of rhodamine B in aqueous solution under simulated solar light.On the basis of our previous work,visible-light active carbon-doped Ti_0.91Zr_0.09O₂ solid solution photocatalysts were also directly obtained by USP method.The characterization results revealed that the carbon doping successfully extended the absorption edges of the solid solution to visible light region.These experiments confirmed that the USP method is suitable to synthesize high-efficiency solid solution photocatalysts in a large scale.