Boqiong Jiang

Low-temperature selective catalytic reduction of NO on MnOx/TiO2 prepared by different methods

Catalysts based on MnO(x)/TiO(2) were prepared by sol-gel, impregnation, and coprecipitation methods for low-temperature selective catalytic reduction (SCR) of NO with NH(3). Among the catalysts, the sample prepared by sol-gel method had the best performance on both activity and SO(2) resistance. From the results of thermo gravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectrum (XPS), it was known that manganese oxides and titania existed in different phase in the samples prepared by three methods. Strong interaction, large surface area, high concentration of hydroxyl groups, high concentration of amorphous Mn on the surface might be the main reasons for the excellent performance of the catalysts.

Photocatalytic reduction of NO with NH3 using Si-doped TiO2 prepared by hydrothermal method.

A series of Si-doped TiO2 (Si/TiO2) photocatalysts supported on woven glass fabric were prepared by hydrothermal method for photocatalytic reduction of NO with NH3. The photocatalytic activity tests were carried out in a continuous Pyrex reactor with the flow rate of 2000mL/min under UV irradiation (luminous flux: 1.1x10(4)lm, irradiated catalyst area: 160cm2). The photocatalysts were characterized by X-ray diffraction (XRD), BET, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) spectrophotometer, transmission electron microscopy (TEM), photoluminescence (PL) and temperature-programmed desorption (TPD). The experiment results showed that NO conversion on Si/TiO2 at 323K could exceed 60%, which was about 50% higher than that on Degussa P25 and pure TiO2. With the doping of Si, photocatalysts with smaller crystal size, larger surface area and larger pore volume were obtained. It was also found that Ti-O-Si bands were formed on the surface of Si/TiO2 and that the surface hydroxyl concentration was greatly increased. As a result, total acidity and NH3 chemisorption amount were enhanced for Si/TiO2 leading to its photocatalytic activity improvement.