| Abstract: | The effect of the Al_2O_3 structure on the performance of Pt/Ga/Al_2O_3 catalysts is investigated for the direct dehydrogenation of propane. The study unveils that the structure of Al~(3+)determines the bulk structure of catalysts, particularly a high content of coordinatively unsaturated Al~(3+)sites(penta-coordinated Al~(3+),denoted as Al~(3+)penta) could lead to a remarkably improved dehydrogenation activity of the catalyst. The bulk characterization reveals that the sufficient amount of Al~(3+)pentain Al_2O_3 benefit the dispersion of Pt and Ga_2O_3 on the Al_2O_3 support. At the same time, TPR results reveal that the presence of Pt facilitates the reduction of Ga_2O_3, likely due to the hydrogen spillover between the well dispersed Pt and Ga_2O_3,which consequently enhances the synergistic function between Pt and Ga_2O_3 in the dehydrogenation of propane. Recyclability tests demonstrate that the dehydrogenation activity stabilizes after three cycles over the Pt/Ga/Al_2O_3 catalyst. |
