Kanattukara Vijayan Bineesh

Selective catalytic oxidation of H2S to elemental sulfur over V2O5/Zr-pillared montmorillonite clay

The performance of vanadia-doped zirconia-pillared clay (V/Zr-PILC) for the selective catalytic oxidation of H2S was investigated in this study. A series of vanadia-doped zirconia pillared clays (V/Zr-PILCs) with various amounts of vanadia were prepared and characterized using X-ray diffraction (XRD), surface area-pore volume measurements, chemical analysis, infrared (FTIR) spectroscopy, UV–vis-diffuse reflectance spectroscopy (UV–vis-DRS), X-ray photoelectron spectroscopy (XPS), and thermogravimetric (TG) analysis. V/Zr-PILCs showed better catalytic performance than Zr-PILC at temperatures ranging from 220–300 °C without any considerable SO2 emission. The H2S conversion over V/Zr-PILCs increased with increasing vanadia content up to 6 wt%. However, it decreased at higher vanadia loadings due to the decrease of surface area and to the formation of the crystalline V2O5 phase. The results of a regeneration experiment using 6 wt% V/Zr-PILC catalyst showed good reproducibility in its catalytic activity, even through five successive sulfidation-regeneration cycles at 280 °C.

Vanadium incorporated into three dimensional KIT-6: optimization of the synthesis procedure and its catalytic applications

Abstract Vanadium was directly incorporated into the three-dimensional framework of KIT-6 by carefully controlling the concentration of HCl, TEOS and the vanadium content. The extent of mesopore structural ordering was confirmed from X-ray diffraction, N 2 physisorption, SEM, and TEM analysis. The coordination and nature of V sites in V-KIT-6 samples are characterized by FT-Raman, UV-visible diffuse reflectance and 51 V spin-echo NMR analysis. The material obtained therein showed very high specific surface area (~1009m 2 /g) and pore diameter (~5.7nm). The catalytic activity of the calcined material was tested in the oxidation of cyclohexane and styrene.