Selective oxidation of isobutane over MO-P-O/SiO2 catalyst

MoO3/SiO2 and Mo-P-O/SiO2 catalysts were prepared by the sol-gel method. The surface composition, activity of lattice oxygen, chemisorption, and activity of the catalysts were systematically studied by using X-ray diffraction, infrared spectroscopy, temperature-programmed reduction, temperature-programmed desorption, and microreactor techniques. The results showed that the active components can disperse on the surface of the catalysts as monolayer. Isobutane is chemisorbed on the surface terminal oxygen of the Lewis base sites Mo=O bonds by one or two H atoms of methyl to form molecular adsorption states. The activity and selectivity of MoO3/SiO2 and Mo-P-O/SiO2 catalysts are high for the selective oxidation of isobutane. The addition of PO43- improves the selectivity for C-4 oxygenate products.