| 초록 |
The hydrogen of high energy density production processes have been much investigated for alternative carbon free energy source instead of fossil fuel based energy system. The fossil fuel based energy system produce CO2 gas during power generation. CO2 gas in atmosphere and sea water change the climate of the earth. Therefore eco-friendly production technique of hydrogen gas is required. Honda and Fujishima have reported the photo-catalytic water splitting using TiO2 powder catalyst in 1972. This report has triggered to study over the world. As photo-catalyst itself should absorb irradiated solar spectrum from the sun, narrow band gap of photo-catalyst is required. Generally solar spectrum is consist of 4% of ultraviolet, 43% of visible light and 53% of infrared. So former wide band gap photo-catalysts such as TiO2, ZrO2, ZnS and SiC can not be used for high efficiency system. Quantum confinement effects of chalcogenide compound based quantum dot as sensitizer show outstanding photo-catalytic activity. However chalcogenide compounds have severely undergone photo-corrosion in photo-electrochemical system. In this study, We have studied photo-corrosion free sensitizer. Reduced graphene oxide quantum dots have applied for visible light driven TiO2 based photo-catalyst. And various dot sizes were studied by FE-TEM, FE-SEM and UV-VIS spectrometer. The stability of reduced graphene oxide quantum dots in photo-electrochemical system was studied by time resolved photo-current density measurement. |
