Electronic density enrichment of Pt catalysts by coke in the propane dehydrogenation

Abstract

We investigated the nature of coke generated in propane dehydrogenation over supported Pt catalysts by FTIR, NMR, and XPS. NMR and FTIR spectra proved that the coke produced in the reaction contained poly-aromatic rings, which was consistent with the previous result that pregraphite-like coke structure was formed. The XPS results indicated that the coke deposits consisted of sp 2 hybridized carbon. All of the characterizations indicated that the pregraphite-like coke containing the poly-aromatic ring structure was generated over the catalysts during the propane dehydrogenation. Furthermore, the XPS measurement demonstrated that the coke deposits interacted with Pt and the electron density of Pt was enriched through the interaction.

Platinum-Tin Nano-Catalysts Supported on Alumina for Direct Dehydrogenation of n-Butane

“…All the reduced nano-catalysts exhibited binding energy of single Pt 4f 7/2 component at 71.3-72.3 eV (not shown here), indicating the presence of zerovalent platinum. 23 This means that all platinum species were completely reduced to zerovalent platinum during the reduction process. Figure 5 shows the binding energies of Sn 3d 5/2 level of reduced Pt/Sn/Al 2 O 3 (X) nanocatalysts.…”

Stable and Selective Dehydrogenation of Methylcyclohexane using Supported Catalytically Active Liquid Metal Solutions – Ga52Pt/SiO2 SCALMS

“…Dehydrogenation is typically carried out on noble metal (e. g. Pt) or oxide (e. g. Cr 2 O 3 ) catalysts . Coke formation requires the presence of vicinal sites on the catalyst surface . Regeneration of the catalyst after coking is possible but causes either reactor downtime or additional investment into stand‐by or reserve reactor equipment.…”

“… Small amount of carbon species may form in the early stage of the catalytic reaction and strongly adsorb on Pt surface and cause poisoning of the active sites The Pt particles undergo sintering.…”

Influence of Oxygen Mobility over Supported Pt Catalysts on Combustion Temperature of Coke Generated in Propane Dehydrogenation

“…Furthermore, the coke located on the Pt has a lower combustion temperature than that on the support because of the catalytic effect of the Pt sites. In our previous report [18,31], 13 C CP/MAS NMR, XRD and TPO techniques were used to demonstrate that the coke structure was independent of the nature of supports in propane dehydrogenation over supported Pt catalysts at 600°. The coke was located mainly on the supports in our experiment because at least two spent catalysts should have similar combustion temperatures if the coke is located on Pt sites.…”