PREPARATION AND CHARACTERIZATION OF VARIOUS TITANIAS (ANATASE) USED AS SUPPORTS FOR VANADIA-SUPPORTED CATALYSTS

Samples of anatase, prepared using different methodologies, and an ind ustrial sample were characterized using X-ray photoelectron spectrosco py, X-ray diffraction analysis, electron microscopy, diffuse reflectan ce spectroscopy, temperature-programmed desorption of ammonia, nitroge n adsorption, microelectrophoresis and potentiometric titrations. It w as found that anatase prepared by hydrolysis of the titanium isopropox ide exhibited the largest specific surface area, the highest Lewis aci dity and the highest concentration of the protonated plus neutral surf ace hydroxyl groups. These hydroxyl groups are considered to be the de position sites for the VO3- ions in the preparation of the V2O5/anatas e catalysts by equilibrium deposition-filtration. The above findings a s well as the absence of foreign ions on the surface of the anatase pr epared by the hydrolysis of titanium isopropoxide renders this materia l the most suitable for preparing the above catalysts used in NO reduc tion.