(692g) Development of a Vanadium Oxides Loading Method on Solid Supports
Vandium oxides have been used as catalysts in diverse reactions such as partial oxidation of hydrocarbons, oxidative dehydrogenation of alkanes to alkenes, oxidation of SO2, and selective catalytic reduction of NOx. Due to the huge importance of vanadium oxide catalysts in oxidation reaction, it is of great interest to improve the catalytic activity and obtain a higher number of active sites. Vanadia is typically deposited onto high area support materials by an impregnation method, grafting or an immobilizing method. Although extensive effort has been made to control the dispersion on supported catalysts, the development of a simple methodology to prepare highly dispersed vanadium loading remains a challenge. Several grafting or immobilizing methods such as vapor deposition and atomic layer deposition under strictly anhydrous organic solvent systems have been developed. However, these methods need complicated devices and long procedures. In this study a direct deposition method of VOCl3 on the solid surface has been studied. The characteristics of the metals loaded catalysts were analyzed with XRD, SEM-EDS, FTIR, and XPS. The amount of loading can be easily controlled in the range of 1~15%. The catalysts prepared by the direct loading method showed a better activity in the transesterification of soybean oil and methanol than the catalysts prepared by the impregnation method or the grafting method. The stability of vanadium oxides depends on the surface nature and loading methods.