Magnetic nano-particles load TiO_2 Photocatalyst and Properties

Title: Magnetic nano-particles load TiO_2 Photocatalyst and Properties Author: Xia Shumei Degree-granting units: Harbin Engineering University Keywords: titanium dioxide;; alkaline earth metal ion doping;; titanate nanotubes;; magnetic;; photocatalytic Summary: Titanium dioxide for its low cost, non-toxic, high catalytic activity, stability, corrosion and other advantages of light received wide attention. However, due to low quantum yield of TiO2, the light response range is narrow, solar energy is low, the difficulty of catalyst separation and recovery of shortcomings limit its practical application. In this paper, nano-titanium dioxide powder catalyst separation and recovery of the difficult problem, choose a large surface area and easy magnetic separation of magnetic nano-powder as a carrier, using a series of sol-gel magnetic Rare earth magnets Photocatalyst agents, and alkaline earth metal ions through doped TiO2 to expand the spectral response range, improve the utilization of sunlight. The magnetic particle loading anatase titanium dioxide as raw materials were prepared by hydrothermal method with the large surface area of ​​titanate nanotubes magnetic composite materials. Using VSM, XRD, TEM, DRS, SEM and other techniques to study the magnetic structure of photocatalyst and catalytic properties of the relationship between the methylene blue to simulate pollutant of catalyst photocatalytic performance. Sol - gel prepared magnetic particles SiO2/MeFe2O4 (SM, Me = Ni, Co, Co0.64Zn0.36) load the composite photocatalyst TiO2/SiO2/NiFe2O4 (TSN), TiO2/SiO2/CoFe2O4 (TSC) and TiO2/SiO2/Co0.64Zn0.36Fe2O4 (TSCZ). Research shows that, TSN, TSC, TSCZ all have ferrimagnetism, easy separation by the magnetic field, http://www.chinamagnets.biz/faq.php with good recovery performance and reusability. The introduction of SiO2 intermediate layer greatly improves the composite photocatalyst photocatalytic performance. Photocatalytic results show, TSN's best catalytic properties of ultraviolet light, TSCZ the best catalytic properties of visible light. Sol - gel prepared by alkaline earth metal ions (M2 +) doped with magnetic load composite photocatalyst M2 +-TSN (M2 + = Mg2 +, Ca2 +, Sr2 +, Ba2 +), systematic study of the alkaline earth metal ion doping on TSN catalytic properties impact. It was found, M2 +-doped TiO2 caused by red-shifted absorption band edge, M2 + doped into the crystal lattice induced lattice distortion, the particle size becomes smaller, Mg2 +, Ca2 +, Sr2 +, Ba2 +, respectively, the optimal doping amount of 1.0%, 1.0%, 0.8%, 0.8%. Photocatalytic experiments showed that alkaline earth metal ions doped to improve the visible light photocatalytic activity of TiO2, Ba2 + doped samples in the visible region of the degradation rate of methylene blue increased nearly 2-fold compared with TSN. Synthesized by hydrothermal method using magnetic particles load titanate nanotubes magnetic composite materials (MTNT), examined the preparation conditions on MTNT morphology, composition, magnetic and catalytic properties. The study found that hydrothermal reaction temperature and NaOH concentration on the formation of MTNT have a significant impact. MTNT mainly composed of Na0.8H1.2Ti3O7. As the SiO2 dissolved in alkali solution, MTNT than the magnetic material has been enhanced. Calcined at 400 ~ 500 ℃, the titanate nanotubes into TiO2 nanotubes. Photocatalytic results show that calcined MTNT activity increased. In the visible light photocatalytic degradation of methylene blue wastewater, by the pH of the system has little effect, MTNT the added amount of raw material 1 / 3 of the methylene blue decolorization rate increased nearly 2-fold. Synthesized by hydrothermal method Ba2 +-doped titanate nanotubes magnetic composite materials (Ba2 +-MTNT). Examined the Ba2 + doping on MTNT of performance. Ba2 + doping on MTNT no significant effect on the morphology, Ba2 +-doped water and heat accelerate the reaction rate and improve the MTNT thermal stability. Ba2 +-doped nanotubes increases the surface area, improve the catalytic properties of nanotubes visible. Ba2 +-MTNT with good catalytic properties in the visible light photocatalytic degradation of methylene blue water, the pH has little effect by the system, adding less catalyst, easy separation by the magnetic field, has good application prospects. Degree Year: 2009