Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE credits
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.
2016. , 98 p.