Studies on the Preparation, Characterization and Catalytic Activity of the Nanosolid Heteropoly Acid H3PW12O40/SiO2 Using the Sol-Gel Method

Abstract

A new nanosolid heteropoly acid H₃PW₁₂O₄₀/SiO ₂has been prepared by using the sol–gel method. The structure of this acid has been studied by infrared (IR) spectroscopy, X-ray diffraction (XRD) methods, transmission electron microscopy (TEM), X-ray photoemission spectroscopy (XPS) and specific area detector analysis. The results show that the nanosolid (diameter: 30–70 nm) is amorphous and has a large surface area (506.5 m² g^-1). Infrared spectra revealed that the skeleton of the heteropoly anion PW₁₂O₄₀^3–still exists in the silica structure. The catalytic activity was measured by monitoring the synthesis of methyl t-butyl ether (MTBE); MTBE was obtained in yields of up to 84.0% and the catalyst remained highly active after five uses.