Hydrogenative reforming of methylcyclopentane (MCP) was performed on both mesoporous BEA and MFI zeolites supported 2.5 nm Pt nanoparticles (Pt/BEA and Pt/MFI, respectively) at various temperatures, room temperature (20 �C), 50 �C, 100 �C and 150 �C, respectively. The average loading of the nanoparticles on the supporting zeolite is 0.4~0.5%. Annealing of the catalysts at 250 �C for one hour allows the removal of the poly (vinylpyrrolidone) (PVP)-capping agent of the Pt nanoparticles. The mesoporous zeolite supported Pt nanoparticles were highly active and selective towards the ring enlargement of MCP molecules. In situ Sum Frequency Generation Spectroscopy (SFG) studies revealed the possible reaction intermediates on both catalysts. At 150 �C, the appearance of the =CH2 , =CH and CH2 modes for the reaction on both catalysts indicates the existence of ring-opening terminal olefin and cyclohexene reaction intermediates; a physisorbed benzene species appeared in the spectrum on Pt/MFI and was not observable on Pt/BEA, which is consistent with the reaction selectivity data. No reaction product was observed at room temperature for both catalysts. SFG results for Pt/MFI at room temperature showed either a reorientation of the MCP molecules or a progressive absorption of the MCP on the catalyst interface in a time scale of ~ 90 min, which was indicated by the intensity change of the CH modes in SFG spectra in three successive scans, as shown in Figure 1.

Molecular insights into the reaction mechanisms: In situ sum frequency generation studies of hydrogenative reforming of methylcyclopentane on zeolite supported 2.5 nm Pt nanoparticles

248th National Meeting (2014)

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