n-Heptane isomerization on a new kind of micro/mesoporous catalyst: Pt supported on HZSM-5/HMS

• The acidity of catalysts increases linearly with HZSM-5 content (0.15–0.50 mmol NH3/g).
• The prepared catalysts have high catalytic activity (50.6–100%) in this reaction.
• Highest i-C7 selectivity (35.8%) was obtained for Pt/ZH-30 at 200 °C.
• Due to good metal dispersion (92.01%), Pt/ZH-30 is better catalyst than Pt/ZH-40.

Pt loaded on a series of ZSM-5/HMS composites with different H-zeolite amounts has been prepared and used as a solid acid catalyst for the catalytic isomerization of n-heptane. The structure characterization, acid distribution and morphology of the Pt catalysts supported on these composite materials were characterized by XRD, XRF, NH3-TPD, SEM, FTIR, Py-IR, H2 chemisorption, nitrogen sorption and TGA (for investigating the coke deposition) techniques. Compared with HMS and HZSM-5, these new composite materials have good ability for n-heptane isomerization. The results show that these micro/mesoporous catalysts have both properties of mesoporous HMS and microporous HZSM-5. The best i-C7 selectivity (35.8%) was observed for Pt/ZSM-5(30)-HMS at T = 200 °C. These new composite catalysts prove the catalytic stability at the reaction time, which results in their thicker pore-wall and appropriate acidity.

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