Zhong Jia-cheng

Photocatalytic Oxidation of Aniline in the Gas Phase Using Porous TiO2 Thin Films

The gas-phase photocatalytic oxidation of aniline on a new kind of porous nano-TiO2 composite films is investigated. The composite film was prepared on glass fiber with the water glass as binders and dilute H2SO4 solution as solidifying reagent. The surface characters were observed by scanning electron microscope. The photocatalytic degradation of aniline on the composite films was carried out in a TiO2/UV system. Some important factors affecting the photodegradation, such as the concentration of TiO2, the initial concentration of aniline, and the existing water vapor, are also studied. The product of photocatalytic oxidation was detected by Fourier transform-Infrared. The partial intermediate products were absorbed on TiO2 surface, which resulted in catalyst deactivation. But when it was irradiated under UV illumination or solar irradiation for some time, the catalyst could be reused without loss of catalytic activity.

Microstructures and optical properties of sol-gel derived TiO2 anatase thin films

TiO2 anatase thin films on quartz substrates were prepared with sol-gel method. The dry gel films, made by spin coating 10 times, were calcined at various temperatures. From X-ray diffraction analyses, it is found that the anatase to rutile phase transformation temperature of the films is higher than 850°C, the films are preferentially oriented on (0 0 1) plane, i. e.c-axis oriented. The thickness, refractive indexes, absorption coefficients and extinction coefficients of the films were determined from UV-Vis transmission spectra of the films using a UV-Vis spectrophotometer. The thickness of the films is about 570 nm. The refractive indexes, absorption coefficients and the extinction coefficients of the present films are larger than the values of anatase films prepared by sputtering. This indicates that the films made with sol-gel method are very dense.

Photocatalytic oxidation of NO x with porous TiO2 nanometer thin film

A new kind of porous nano TiO2 composite films was prepared on the glass substrate with the water glass as binders and the sodium fluorosilicate as solidifying reagent. The morphologies of the films were studied by scanning electron microscope(SEM). The UV Vis spectrophotometer was also used to investigate the absorption of the films. The gas phase photocatalytic oxidation of nitrogen oxides on the com posite film was carried out in TiO2 UV system, and some important factors affecting the photocatalytic oxidation were also studied such as the catalyst, concentration vapor pressure and the presence of oxygen. The results showed the conver sion of NOx reached 97.5°, after 2 h UV irradiation. The final product of photo oxidation was detected to be HNO3 by FT-IR. The way of photocatalytic oxidation of NOx was possibly useful in the practical application.

Laser cooling using anti-stokes fluorescence in Yb3+-doped fluorozirconate glasses

The fluorozirconate glasses ZBLANP (ZrF4−BaF2−LaF3−NaF−PbF2) doped with different Yb3+ concentration were prepared. The Raman spectra and absorption spectra are measured to substantiate the existence of phonon-assisted emission. After analyzing the normalized absorption spectra of samples with different Yb3+-doped concentration, we calculated the maximum cooling effect in the 3 wt% Yb3+-doped sample pumped at 1 012.5 nm. The corresponding cooling capability is about −4.09 °C/W and the cooling efficiency reaches 1.76%.

The energy transfer in Pr3+/Yb3+ Co-doped fiber amplifier

The absorption spectrum of Pr 3+ and Pr 3+ +Yb 3+ , the fluoresce wavelength of Pr 3+ in ZBLAN glass have been measured. The energy transfer process in the Pr 3+ /Yb 3+ co\|doped fiber amplifier has been analyzed, and the probability of energy transfer between Pr 3+ and Yb 3+ has also been calculated using by electric multi\|pole interaction theory. By discussing the energy transfer rate related to the rare\|earth ion concentration and the pump wavelength, the best concentration and pump wavelength are obtained for the optimised fluores cence at 1.3 μm and the most efficent gain of fiber amplifier.