Abstract
A series of vanadia-doped zirconia-pillared clays (V/Zr-PILCs) with various amounts of vanadia were prepared and their performance for the selective catalytic oxidation of H2S was investigated in this study. V/Zr-PILCs were characterized using X-ray diffraction (XRD), surface area-pore volume measurements, chemical analysis, X-ray photoelectron spectroscopy (XPS), V-51 spin-echo NMR, temperature-programmed reduction by H-2 (H-2-TPR) and temperature-programmed desorption of ammonia (NH3-TPD). V/Zr-PILCs showed better catalytic performance than as such Zr-PILC at temperatures ranging from 220 to 300 degrees C without any considerable SO2 emission. The H2S conversion over V/Zr-PILCs increased with increasing vanadia content up to 6 wt.%. This superior catalytic performance might be related to the uniform dispersion of vanadia in the form of monomeric and polymeric species. However, it decreased at higher vanadia loadings due to the decrease of surface area and to the formation of crystalline V2O5 phase. The presence of water vapor in the reactant mixture resulted in the decrease of the H2S conversion. (C) 2009 Elsevier B.V. All rights reserved.