Preparation of γ-Al2O3 via Hydrothermal Synthesis Using ρ-Al2O3 as Raw Material for Propane Dehydrogenation

Abstract

γ-Al2O3 was prepared by hydrothermal synthesis using ρ-Al2O3 and urea as raw materials. In this work, the effects of the molar ratio of CO(NH2)2/Al and reaction temperature were investigated, and a Pt–Sn–K/γ-Al2O3 catalyst was prepared. The ammonium aluminum carbonate hydroxide (AACH), γ-Al2O3, and Pt–Sn–K/γ-Al2O3 were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N2 adsorption–desorption, thermogravimetry–differential thermal analysis, and NH3 temperature-programmed desorption techniques. The reactivity of Pt–Sn–K/γ-Al2O3 for propane dehydrogenation was tested in a micro-fixed-bed reactor. The results show that γ-Al2O3 with a specific surface area of 358.1 m2/g and pore volume of 0.96 cm3/g was obtained when the molar ratio of CO(NH2)2/Al was 3:1 and the reaction temperature was 140 °C. The alumina obtained by calcination of AACH has a higher specific surface area and larger pore volume than the industrial pseudo-boehmite does. The catalyst prepared from AACH as precursor showed high selectivity and conversion, which can reach 96.1% and 37.6%, respectively, for propane dehydrogenation.