Highly active Iron oxide based oxygen evolving Catalyst for Artificial photosynthesis under Visible Light

Abstract

There are interests for development of sustainable energy supply because of CO2 emission and high oil price problem. The conversion of CO2 into high-value useful products like methanol is highly desirable and timely and it is in-line with international environmental protection agency and united nation regulations. The photo-reduction of CO2 by H2O is one of the key chemical reactions for the generation of renewable fuels using light as an energy source. The development of process called artificial photosynthesis converting carbon dioxide into useful chemical like methanol or methane was conducted. The artificial photosynthesis system consists of water oxidation to make proton and electron from water, charge separation without recombination, and fuel forming reaction. The initial step for this process is the photo oxidation of water. We did experiments to develop water-oxidation catalysts have high efficiency under visible light illumination. We prepared the catalysts via photo-chemical deposition by TiO2 activation through UV light irradiation to locate metal species at activation site. By change of solution condition, we prepared different catalysts showing different catalytic activity. When using phosphate solution, the prepared catalysts containing both Fe oxide and phosphate have high activity for oxidation of water under visible light irradiation. We did XRD, XPS and DR-UV-vis spectra analysis to characterize the prepared catalysts. The prepared catalysts can absorb the visible light region response to surface treatment with formation of iron species. We couldn’t find peak related to Fe oxide before heat treatment. We found the reason for this tendency in previous study. They told that the peak of metal oxide was disappeared as phosphate components growing up. In conclusion, we prepared the water oxidation catalysts for artificial photosynthesis system. The mimicked Z scheme in nature photosynthesis system. Inorganic sensitizer was prepared on TNT and the...