Book Description

Recently, a highly efficient photocatalyst consisting of amorphous manganese oxide (AMO) has been developed. Photoassisted catalytic oxidation of isopropanol has been studied by using amorphous manganese oxide catalysts with magnesium oxide as a diluent. When AMO or AMO/MgO is illuminated with UV-visible light in the presence of isopropanol vapor and oxygen at room temperature, the primary organic oxidation product is acetone. Enhanced yields for photooxidation of isopropanol with AMO/MgO mixtures have been observed. A continuous supply of oxygen may be achieved by adsorbing molecular oxygen on AMO and AMO/MgO during simultaneous irradiation in the UV-visible range. Temperature programmed desorption and oxygen isotopic exchange results support previously proposed mechanisms of photoassisted catalytic oxidation. Oxygen is adsorbed as O$\sb2\sp-$ species on the surface of the catalyst and plays an important role in this photooxidation. The observed effect of magnesium oxide suggests that hydroxyl groups promote the catalytic activity. The contamination of indoor air by volatile organic compounds (VOCs) has become a serious public health problem in recent years. The purpose of this study is to investigate photocatalytic activity of TiO$\sb2$ under kinetic conditions and the application of photocatalysts for decomposition of VOCs. The photocatalytic degradation of trichloroethylene, toluene, and triethylamine over TiO$\sb2$ (anatase) has been investigated by using a flat plate photochemical reactor. TiO$\sb2$ was used as a thin film coated on a microscope slide. The degradation of the three compounds, trichloroethylene, toluene, and triethylamine in a continuous flow mode, approximates first-order kinetics. The Langmuir-Hinshelwood kinetics have been used to rationalize the first-order behavior in solid-gas reaction. The deactivation of the catalyst also was investigated.