Binary Cr–Mo oxide catalysts supported on MgO-coated polyhedral three-dimensional mesoporous SBA-16 for the oxidative dehydrogenation of iso-butane Original Research Article

Binary Cr–Mo oxide catalysts (denoted as Cr(x)Mo(y), x/y = nominal Cr/Mo molar ratio) supported on MgO-coated polyhedral three-dimensional (3D) mesoporous SBA-16 (MS) were fabricated for the oxidative dehydrogenation of iso-butane. The materials were characterized by a number of techniques for the establishment of the relationships between physicochemical properties and catalytic performance. The use of high-surface-area 3D MS as support for Cr–Mo oxide catalysts leads to increases of catalytic activity and of selectivity to iso-butene. The Cr(x)Mo(y) catalysts show higher iso-butene yield than the Cr/MS or Mo/MS catalyst. Under the conditions of iso-butane/O2 molar ratio = 1/2, space velocity = 30,000 mL/(g h), and reaction temperature = 540 °C, maximal iso-butene yield of 7.5% (iso-butane conversion = 10.0% and iso-butene selectivity = 75.0%) can be achieved over the Cr3Mo1 catalyst. Based on the results of characterization and activity evaluation, we conclude that the excellent catalytic performance can be attributed to the moderate basicity, good dispersion of CrOx and MoOx, high Cr6+ content, and high initial H2 consumption rate of Cr3Mo1.