This study investigates the surface modification of photocatalysts and the photoreduction of CO2 to convert to useful fuels or chemicals under ultraviolet (UV) illumination. The photocatalysts used in this study are Ag/TiO2 and Cu/TiO2 made by the impregnation method, and the wavelength of UV irradiation is 254 nm. An X-ray single crystal diffractometer, scanning electron microscope, energy dispersive spectrometer, X-ray photoelectron spectroscopy or Electron Spectroscopy for Chemical Analysis and BET surface measurement devices are used for the characterization of Cu/TiO2 and Ag/TiO2. These analyses prove that the elements of Ag and Cu are all in the form of a zero charge, such as Ag0 and Cu0. The photocatalytic reductions of CO2 are performed for three different cases. The major product in the Na2CO3 solution with the photocatalysts is methanol, and the gas product is methane with the yield 125 µg g-1 at 1 M CuCl2 and 0.1 M Na2CO2. For the reaction mechanism, CO2 is assumed to be adsorbed on the surface of the photocatalysts and combines with the electron which is excited from the photocatalytic reaction via the forming of ·CO2-. After the forming of ·CO2-, the intermediates of ·CO+ and OH- produce the products of CH3OH and CH4. The results obtained from this study contribute to a better understanding of the UV/photocatalytic process for the reduction of CO2. The technology for the reduction of CO2 to useful fuels and chemicals as elucidated in this study is also environmentally beneficial.
|頁（從 - 到）||237-246|
|期刊||Sustainable Environment Research|
|出版狀態||已出版 - 2012|