Catalytic performance of gallium oxide based-catalysts for the propane dehydrogenation reaction: effects of support and loading amount

Abstract

The different materials (ZSM-5, SBA-15, γ-Al2O3 and SiO2) were used as supports for Ga2O3-based catalysts for the propane dehydrogenation reaction, and the effect of Ga2O3 content (1-9 wt%) for xGa2O3/SBA-15 catalysts on the catalytic activity was discussed. It is found that the supports determine the porous features, the state and dispersion of Ga species, and the acid-base properties of the corresponding catalysts. The existence of strong acid sites in catalyst can lead to more well-dispersed Ga species. The satisfied catalytic performances are obtained over 5Ga2O3/ZSM-5 and 5Ga2O3/SBA-15 catalysts. Among the Ga2O3-based catalysts with different supports, the 5Ga2O3/ZSM-5 sample exhibits the highest catalytic activity, which possesses the maximum well-dispersed gallium species and high dehydrogenation efficiency gallium ions (Gaδ+ cations, δ < 2), and the 5Ga2O3/SBA-15 catalyst exhibits the highest catalytic stability. Furthermore, as for the xGa2O3/SBA-15 samples, the 5Ga2O3/SBA-15 sample exhibits the best catalytic performance. The initial propane conversion and propylene selectivity are above 32.0% and 90.0% respectively, and a final propane conversion of 17.0% is obtained after 30 h reaction. With the increase of Ga loading, the Ga species are easily agglomerated and destroy the structural integrity of the SBA-15 support, which is unfavorable to the propane dehydrogenation reaction.