J.G. Hernández-Cortez

Effect of Ga in the photocatalytic properties of TiO2

In this work we prepared a series of GaZn/TiO2 (5 wt%, 10 wt%, and 15 wt% of Ga) photocatalysts by the sol-gel method. The X-ray diffraction results showed the presence of TiO2 in anatase phase. Also, in the GaZn/TiO2 system a small peak assigned to Ga2O3 is present. The specific surface area of the Zn/TiO2 is 97 m2/g and the specific surface area increases to 132 m2/g when the amount of Ga increases. The energy band gap values obtained by UV-VIS diffuse reflectance spectroscopy are 2.9, 3.12 and 3.15 eV for 5GaZn/TiO2, 10GaZn/TiO2 and 15GaZn/TiO2 respectively. The results of the photocatalytic activity show that the total destruction of phenol is more efficient in GaZn/TiO2 than in the Zn/TiO2 photocatalysts.

Production of Di-isopropyl ether (DIPE) over 12-Molybdophosphoric Acid Supported on ZrO 2 . An Alternative Octane Enhancer for Lead-free Petrol

Solid acid catalysts of 12-Molybdophosphoric acid (MoP) supported on hydrous zirconia have been synthesized using impregnation method. Structural transformations due to thermal effects have been studied by different techniques including X-Ray diffraction, thermogravimetric analysis (TGA), infrared absorption (DRIFT), Raman spectroscopy and 31 P MAS NMR. These techniques showed that the heteropolyacid present undegraded Keggin structure. The transformation of heteropoly anion of pure HPMo to MoO 3 begins at a temperature lower than that for its ZrO 2 -supported counterpart. The activity of ZrO 2 -supported (MoP-Z) catalysts in the 2-propanol decomposition presents a high selectivity to the formation of DIPE and propene, this selectivity is related with acid sites determined by thermodesorption (TPD) of NH 3 .