Photocatalytic Hydrogen Production From Water With Simultaneous Degration Of Pollutant

Photocatalytic hydrogen evolution by light energy of sun is one of the effective solutions of the energy problems in the 21st century. Most photocatalysts need to add electron donors to restrain the recombine of the electrons-holes and the reverse reaction of hydrogen and oxygen. Use pollutions in water as electron donors, H2 production is promoted and organic waste is oxygenated into CO2 and H2O. It reduces the cost of the H2 production and decomposes of the pollutants at the same time.TiO2 (P25) and Bi0.5Y0.5VO4 were used as photocatalyst, and Pt was loaded by H2PtCl6. Triethylamine, ethyl ether and alcohols were chosen as decomposition aims. The Xe lamp was used as light sources. Gases were test by gas chromatogram.In the photocatalytic experiences using pollutants as sacrificial reagents, compare the H2 evolutions with and without photocatalyst, and H2 evolution of the pure water to confirm the sacrificial role of the organic pollutants. 0.1mol/L triethylamine and ethyl ether solutions can improve quantum efficiency greatly. The H2 evolution reduced when the reaction progressed and reach a stable quantity after 12 hours, but it's still more than the H2 produced by the pure water. Different sacrificial reagent concentrations of 0.1mol/L,0.06mol/L,0.02mol/L can effect the reaction efficiency directly. H2 evolution reduced when the concentration reduced. PH in the reaction was tested, and the change of pH by HCl and NaOH can also affect the quantum efficiency. The products were characterized by Raman spectroscopy. The change of ethyl ether solution concentration was characterized by UV-vis spectrophotometer. The degradation of ethyl in aqueous solution accords with the first pre-grade kinetics equation. A possible reaction mechanism was discussed.In the photocatalytic experiences using methanol and ethanol as sacrificial reagents, hydrogen produced was tested by GC. Methanol and ethanol can be used as sacrificial reagents. And methanol is better than ethanol. Methanol solution with different concentrations was studied in the experiment. At last the visible photocatalyst Bi0.5Y0.5VO4 was used in the experiments, and methanol can also play the role of sacrificial reagent. Possible reaction mechanism of alcohol was investigated, and the source of the hydrogen atom was discussed.In certain experiment conditions, triethylamine, ethyl ether and alcohols are good sacrificial reagents. They can improve the separate efficiency of electrons-holes. Amount of H2 evolution was increased while the pollutants were decomposed. The process could be used for combined production of H2 and degradation of organic pollutants present in water.