Synthesis of Fe/TiO2 photocatalyst with nanometer size by solvothermal method and the effect of H2O addition on structural stability and photodecomposition of methanol

The nanometer particles of Tio(2) and Fe/TiO2 With a high photo-catalytic activity were obtained by the solvothermal method. The TiO2 and Fe/TiO2 particles were characterized with XRD, SEM, DLS, TG-DSC, and UV-Vis spectroscopy. The TiO2 and Fe/TiO2 particles exhibited an uniform anatase structure with particle size below 50 nm after synthesis at 300degreesC for I h without any treatments. Attained Fe/TiO2 particles had a higher hydrophilic property compared with TiO2, and they absorbed wavelength above 350 run. In photodecomposition of methanol, the methanol was decomposed to CO, HCHO, 2H(2)O, and H-2 as intermediates. Finally, these were transferred into 2CO(2), 2H(2)O, and 2H(2), While, when H2O was added as a reactant with methanol, the intermediates were CO2, HCOOH, H2O, and 3H(2), and then these were converted to 2CO(2), H2O, and 4H(2). In particular, the methanol conversion enhanced about 20% with 10-mol% H2O addition over Fe/TiO2 catalyst compared with pure TiO2. On the other hand, for Fe/TiO2, the anatase structure was stable in 10-mol% H2O addition as a reactant, but it was transferred into the rutile structure with an increase of added H2O amount. In particular, in this study, it was found that the anatase structural change is generated by H2O addition and, as the result, the partially structural change into rutile type could be better effected to photo-degradation for methanol over Fe/TiO2. In addition, we could confirm that the added H2O molecule on the photoreaction over Fe/TiO2 plays a role of supplication of OH radical. (C) 2002 Elsevier Science B.V. All rights reserved.