Superior photodecomposition of pyrene by metal ion-loaded TiO2 catalyst under UV light irradiation
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The photocatalytic degradation of pyrene under UV (125 W Hg-Arc, 10.4 mW/cm2) irradiation of TiO2 aqueous suspension has been found to be highly improved with the dissolved transition metal ions like Cu2+, Fe3+, Ag+, and Au3+, etc. As the reduction potential of these metals lies below the conduction band (CB) position (−0.1 eV) of TiO2, the photoexcited electron transfer occurs more readily and reduces electron–hole recombination rate. Therefore, it has a beneficial influence on the photocatalytic ability of TiO2 because of rapid Fermi energy equilibrium between the CB of TiO2 and its surface adsorbed metal ions.
Results and discussion
The Fermi level is referred to as the electrochemical potential and plays an important role in the band theory of solids. When metal and semiconductor are in contact, electron migration from photoirradiated semiconductor to the deposited metal occurs at the interface until two Fermi levels equilibrate and enhanced the photocatalytic activity of semiconductor photocatalyst. Ni2+ having more negative reduction potential (−0.25 eV) than the CB of TiO2 imparts negligible co-catalytic activity to TiO2 photoreaction. It also revealed that loading of Au3+ ions displayed higher degradation rate of pyrene than Au photodeposition. Furthermore, when the amount of dissolved Fe+3 and Au3+ ions gradually increases from 0.1 to 2 wt.%, the pyrene photodecomposition rate also become faster.
KeywordsTiO2 photoactivity Pyrene photodecomposition Preadsorbed pyrene Metal-loaded TiO2 catalyst Photocatalytic degradation of pyrene Metal ions-TiO2 photoactivity
We are extremely thankful to Degussa Company, Germany for the gift sample of P-25 TiO2 powders.
- Kumar V, Kothiyal NC (2011) Distribution behaviour of polycyclic aromatic hydrocarbons in roadside soil at traffic intercepts within developing cities. Int J Environ Sci Tech 8:63–72Google Scholar