Mesoporous Gallium-Based Catalysts for Oxidative Dehydrogenation of Propane in the Presence of Carbon Dioxide

Abstract: The present study investigates a series of gallium-based catalysts supported on natural and composite aluminosilicate mesoporous supports in the CO₂-assisted oxidative dehydrogenation of propane. The catalyst supports were prepared by mixing a functional material with a boehmite binder, the functional materials being derived from natural halloysite nanotubes (HNTs). Three different supports were used: pristine HNTs; HNTs with MCM-41 synthesized around halloysite; and HNTs with MCM-41 synthesized inside the halloysite lumen. The CO₂-assisted oxidative propane dehydrogenation was tested in the range of 550–700°C at a CO₂/C₃H₈ molar ratio of 2.0. All the catalysts showed comparable propane conversion (from 10–13% to 70–80%) and propylene selectivity (from 80–84 to 30–32%). The highest propylene space-time yield (6.5 mol kg_cat^–1 h^–1) was observed for the Ga/HNT catalyst at 650°C.