To reduce the side reactions and increase the olefin selectivity in the dehydrogenation process, a series of low-loaded Pt-based catalysts supported on θ- Al2O3 (with or without Potassium (K) modification) were prepared. The K modification effect on the n-hexane dehydrogenation performances of Pt/Al2O3 catalysts was investigated using various techniques. The added K species selectively occupied the strong acid sites on the Pt/Al2O3 surface, leading to not only the regulated surface acid properties but also the modified metallic function. Specifically, adding an appropriate amount of K reduced the number of acid sites and increased the electron cloud density of Pt sites, leading to enhanced selectivity and stability. Furthermore, the moderate amount of acid sites kept Pt highly dispersed and a suitable geometric structure, resulting in good activity. Herein, the Pt-0.8K/Al2O3 catalyst with the suitable metal-acid sites balance shows an n-hexane conversion of 25% with over 70% C6 olefin selectivity. More importantly, a significantly low deactivation rate at 500 °C for 30 h is superior to most previously reported.

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