Characterization of redox and acid properties of mesoporous Cr-TiO2 and its efficient performance for oxidative dehydrogenation of propane

Mesoporous Cr-TiO2 materials with chromium content from 0.02 to 0.30 (Cr/Ti molar ratio) were synthesized using a nonionic Pluronic F127 surfactant, and the mesostructure was confirmed by BET, SAXS and TEM. The stability of the mesoporous structure under the atmospheres of propane oxidative dehydrogenation (PODH) and air was investigated. The variety in valence states and the distribution of Cr species on the surface were also evaluated by WXRD, XPS, UV-vis and H-2-TPR methods. The acid properties including kinds, number and strength were measured by NH3-TPD and IR-Py experiment. Propane oxidative dehydrogenation to propylene employed as a probe reaction suggested that the catalytic performance relates closely with the content of Cr, the easily reducible soluble Cr species, and the modification of the acid properties on the surface, while TiCr0.15 catalyst performs good conversion and selectivity, with a yield of propylene near 19%. (C) 2012 Elsevier B.V. All rights reserved.