Insertion of Porous Chromia in γ-Zirconium Phosphate and Its Catalytic Performance in the Oxidative Dehydrogenation of Propane

Abstract

An expanded phase of acetate−hydroxide of Cr(III) intercalated into γ-zirconium phosphate has been isolated by refluxing a solution formed by chromium(III) acetate−hydroxide and γ-zirconium phosphate, previously dispersed in 1:1 water−acetone solution at 353 K. By calcination of this phase at 623 K under vacuum, an intercalated compound with a basal spacing of 1.73 nm and a surface area of 147 m2 g-1 was obtained. A temperature-programmed reduction study reveals that this solid contains a little amount of chromium in high oxidation state. However, when the precursor is heated at 673 K, a collapsed structure with a low surface area was obtained. The inserted porous chromia in γ-zirconium phosphate calcined at 623 K is active in the oxidative dehydrogenation of propane at 623 K with 58% conversion and 10% of selectivity to propene. When this material is calcined at 823 K in air, it is also active in this reaction but only at high temperature, 823 K being necessary to attain catalytic properties similar to t...