| 초록 |
V2O5-TiO2 catalysts with V2O5 contents ranging from 6 to 18 wt% were obtained by calcination at 773 K of xerogels prepared by a nonhydrolytic sol–gel route from VOCl3, TiCl4, and iPr2O. These materials were characterized by X-ray diffraction, micro-FT-Raman spectroscopy, static 51V NMR, SEM, N2 physisorption, temperature-programmed desorption of ammonia (NH3-TPD), and temperature-programmed reduction by H2 (H2-TPR). In all cases mesoporous solids were obtained with specific surface areas up to 87 m2 g-1. Up to a critical V2O5 loading (between 10 and 12 wt%), all the vanadium was highly dispersed in the form of monomeric vanadyl and polymeric vanadate species, whereas for higher loadings V2O5 crystallites also formed. The catalytic properties of these materials were evaluated in the selective catalytic oxidation of H2S. The conversion of H2S was over 92% at 220-300℃ with the reactant composition of H2S/O2/H2O/He = 5/2.5/20/72.5 and GHSV = 30,000 h-1. The yield of solid products, ammonium thiosulfate and elemental sulfur was close to 100%, and there was no considerable amount of SO2 emission. |
