Dehydrogenation of propane over spinel-type gallia-alumina solid solution catalysts

Abstract Dehydrogenation of propane to propylene in the presence or absence of carbon dioxide was performed over a series of mixed Ga x Al 10− x O 15 oxides (with x varying from 0 to 10) synthesized through an alcoholic coprecipitation pathway. Among the various compositions of Ga x Al 10− x O 15 , the maximum activity was observed for x = 8 . Whereas the same tendency was observed for the specific activity normalized by BET surface area, significantly enhanced stability was achieved for Ga 2 O 3 –Al 2 O 3 with higher aluminum content. A correlation between the NH 3 -TPD results and the initial activity for Ga x Al 10− x O 15 reveals that a high population of surface acid sites related to tetrahedral Ga 3+ cations is important to achieving high activity. The specific interaction between Ga 2 O 3 and Al 2 O 3 due to the formation of spinel-type γ -Ga 2 O 3 –Al 2 O 3 solid solutions is suggested to play a key role in the dispersion and distribution of surface gallium sites, which makes Ga x Al 10− x O 15 composites highly active and stable for the reaction.