Synthesis, characterization and catalytic performance of vanadia-doped delaminated zirconia-pillared montmorillonite clay for the selective catalytic oxidation of hydrogen sulfide

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 H 2S 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), 51V spin-echo NMR, temperature-programmed reduction by H 2 (H 2-TPR) and temperature-programmed desorption of ammonia (NH 3-TPD). V/Zr-PILCs showed better catalytic performance than as such Zr-PILC at temperatures ranging from 220 to 300 °C without any considerable SO 2 emission. The H 2S 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 V 2O 5 phase. The presence of water vapor in the reactant mixture resulted in the decrease of the H 2S conversion.