Abstract: MoPO-AlPO₄ catalysts were prepared by sol-gel and impregnation methods. The effects of Mo species on crystal lattice oxygen activity and catalytic performance of MoPO-AlPO₄ for selective oxidation of isobutene were investigated. The catalysts were characterized by N₂ adsorption-desorption, X-ray diffraction, high resolution transmission electron microscopy, Fourier transform infrared spectroscopy, and temperature-programmed reduction. The results showed that the MoPO-AlPO₄ prepared by the sol-gel method existed as mesostructured nanoparticles with larger surface area and more pores than the corresponding MoPO-AlPO₄ prepared by the impregnation. Mo species appeared in tetrahedral coordination in the sample prepared by the sol-gel method and in both tetrahedral and octahedral coordinations in the sample prepared by impregnation. This indicated that the sample prepared by the sol-gel method had better dispersion of Mo species than that prepared by impregnation. The Mo species incorporated-mesoporous AlPO₄ obviously improved the catalytic performance of MoPO-AlPO₄ for selective oxidation of isobutene.

Key words: sol-gel method, impregnation, mesoporous aluminophosphate, isobutene, selective oxidation