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The synergistic effect between metal and acid sites has been considered to be of great importance to n-alkane hydroisomerization catalyzed by bifunctional catalysts. Herein, we report a facile mercaptosilane-assisted in situ synthesis approach to achieve stable and highly dispersed small Pt nanoparticles supported on HL zeolite catalysts (Pt/HL-SH) for n-hexane hydroisomerization. In comparison with the catalysts (Pt/HL-C) synthesized by a traditional ion-exchange method, the Pt/HL-SH catalysts show both high activity and excellent catalytic stability and also no obvious sintering of Pt nanoparticles is observed during the reaction due to the fact that the Pt/HL-SH catalysts possess both higher dispersion of Pt particles within the HL nanocrystals and more mesopores produced by mercaptosilane. Moreover, the regeneration stability of n-hexane hydroisomerization over Pt/HL-SH catalysts was also examined by five continuous cycles, demonstrating excellent regeneration properties. Thus, the mercaptosilane-assisted in situ synthesis approach is a promising way to prepare bifunctional catalysts for enhancing their catalytic performance in n-alkane hydroisomerization. [ABSTRACT FROM AUTHOR]

Incorporating mesopores into ZSM-5 zeolite to form a hierarchical structure has been regarded as an important approach to enhance the diffusivity and catalyst lifetime for light alkane aromatization. Herein, hierarchical ZSM-5 nano-aggregated microspheres were simply and directly synthesized and characterized using TPAOH as a single template without any mesoporous templates or zeolite seeds. The size of the ZSM-5 microspheres and the distribution of mesopores could be regulated by controlling the alkalinity of the synthesis gel. A possible self-assembly mechanism was proposed based on tracing the formation process of ZSM-5 microspheres with crystallization time. The ZSM-5 microspheres modified with Zn were applied in n-hexane aromatization and exhibited better catalytic stability than conventional mono-dispensed microporous ZSM-5 due to the existence of accessible mesopores. [ABSTRACT FROM AUTHOR]