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Selective reforming of methylcyclopentane on Pt model catalysts: The effet of the particle size and surface acidity
KTH, School of Chemical Science and Engineering (CHE).
2016 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesisAlternative title
Selektiv omvandling av metylcyklopentan på modellkatalysatorer av Pt: Påverkan av partikelstorleken och ytsurheten (Swedish)
Abstract [en]

Herein, the selective catalytic methylcyclopentane (MCP) reforming reaction was studied on

monodispersed model platinum (Pt) catalysts. Colloidal Pt nanoparticles were synthesized in

the 1.5-10 nm regime and supported on various synthesized mesoporous supports. The

synthesized heterogeneous catalysts were then evaluated over the reforming reaction using a

home-built flow reactor working at atmospheric pressure and a temperature range of 200-240

℃ . Three different catalytic parameters were evaluated: Pt particle size, surface acidity of the

catalytic supports and the accessibility of the surface acid sites. In this study these parameters

were shown to have an effect on the catalytic selectivity and activity of the reforming

reaction. The results showed that the MCP reforming reaction was particle size dependent,

where 1.5 nm Pt particles supported on mesoporous silica (MCF-17) produced almost

exclusively C6 isomers (2-methylpentane, 3-methylpentane and n-hexane), whereas larger

nanoparticles (7.6 nm) started producing benzene.

The surface acidity was shown to play a major role on the reaction selectivity, where 1.5 nm

Pt nanoparticles supported on mesoporous aluminosilicate materials provided a high

selectivity towards benzene formation. The aluminated MCF-17 support, which was the most

acidic material of the evaluated supports showed the highest benzene production. The change

in reaction selectivity was attributed to the number of Brønsted surface acid sites of the acidic

support through a pyridine probed FT-IR study, which was linked to the Si/Al ratio of the

aluminosilicate supports. The results points towards a bifunctional mechanism, where both the

acid sites and the Pt metal sites were needed for the production of benzene.

The accessibility towards the Brønsted surface acid sites was also evaluated by supporting 1.5

nm Pt particles on ZSM-5 zeolites containing different pore structures. The results showed

that the catalyst containing the largest pores produced more benzene than the catalysts

containing the smallest pores. Initial catalytic results seem to indicate that this effect can be

correlated to the pore size of the supporting materials, however, more studies needs to be done

in order to confirm this effect.

Various characterization techniques have been used throughout this thesis including:

TEM, XRD, N2 physisorption, ICP and pyridine FT-IR.

Place, publisher, year, edition, pages
2016. , 98 p.
National Category
Engineering and Technology
URN: urn:nbn:se:kth:diva-190918OAI: diva2:953717
Available from: 2016-08-18 Created: 2016-08-18 Last updated: 2016-09-22Bibliographically approved

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