Comparisons of propylene and propyne catalytic oxidation on a 100 Å Pt/Al2O3 thin film using in situ soft X-ray fluorescence methods

Burnett, Daniel J.; Gabelnick, Aaron M.; Marsh, Anderson L.; Fischer, Daniel A.; Gland, John L.

doi:10.1016/j.susc.2004.02.004

Cited by 11 publications

(14 citation statements)

References 24 publications

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“…Based on the fluorescence yield near edge spectroscopy (FYNES) experiments, propyne was found to be adsorbed through the p system, with the methyl group orientated up from the Pt surface plane. 31 However, the adsorbed propyne was quite active. At room temperature, it was reported that propyne was converted to propylidyne in the presence of hydrogen on the catalyst surface.…”

Section: Introductionmentioning

confidence: 99%

“…32 The recent theoretical calculations were consistent with their experimental results. [30][31][32][33][34][35][36] Based on the Brønsted-Evans-Polanyi (BEP) relationship, the activation energy can be estimated from the reaction heat. 33,35 Valca´rcel et al 36 studied the thermodynamics of the dehydrogenation of propylene on Pt(111) through density functional theory (DFT) calculations.…”

Section: Introductionmentioning

confidence: 99%

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DFT study of propane dehydrogenation on Pt catalyst: effects of step sites

Yang

Zhu

Fan

et al. 2011

Phys. Chem. Chem. Phys.

195

254

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Self-consistent periodic slab calculations based on gradient-corrected density functional theory (DFT-GGA) have been conducted to examine the reaction network of propane dehydrogenation over close-packed Pt(111) and stepped Pt(211) surfaces. Selective C-H or C-C bond cleaving is investigated to gain a better understanding of the catalyst site requirements for propane dehydrogenation. The energy barriers for the dehydrogenation of propane to form propylene are calculated to be in the region of 0.65-0.75 eV and 0.25-0.35 eV on flat and stepped surfaces, respectively. Likewise, the activation of the side reactions such as the deep dehydrogenation and cracking of C(3) derivatives depends strongly on the step density, arising from the much lower energy barriers on Pt(211). Taking the activation energy difference between propylene dehydrogenation and propylene desorption as the descriptor, we find that while step sites play a crucial role in the activation of propane dehydrogenation, the selectivity towards propylene is substantially lowered in the presence of the coordinatively unsaturated surface Pt atoms. As the sole C(3) derivative which prefers the cleavage of the C-C bond to the C-H bond breaking, propyne is suggested to be the starting point for the C-C bond breaking which eventually gives rise to the formation of ethane, methane and coke. These findings provide a rational interpretation of the recent experimental observations that smaller Pt particles containing more step sites are much more active but less selective than larger particles in propane dehydrogenation.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

DFT study of propane dehydrogenation on Pt catalyst: effects of step sites

Yang

Zhu

Fan

et al. 2011

Phys. Chem. Chem. Phys.

195

254

View full text Add to dashboard Cite

show abstract

“…Because the creation of active metallic sites is completed at the catalytic start-up temperature, the catalytic reaction on the metallic Pt surface must be considered in this case. It is well known that C 3 H 6 exhibits a self-poisoning effect in the C 3 H 6 -NO-O 2 and C 3 H 6 -O 2 reactions on a Pt catalyst, as revealed by kinetic and spectroscopic studies [51][52][53][54][55][56][57]. Carbonaceous species derived from C 3 H 6 are adsorbed on Pt and inhibit the catalytic reaction by blocking the active site.…”

Section: Discussionmentioning

confidence: 99%

Operando X-ray absorption spectroscopy study of supported Pt catalysts during NO reduction by hydrocarbons

Tanabe

Nagai

Dohmae

et al. 2011

Applied Catalysis B: Environmental

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“…100,101 Skeletal oxidation of both propene and propyne proceeds via a C 3 H 4 propyne-like intermediate >370 K, with similar behaviour observed over a 10 nm Pt/Al 2 O 3 thin film catalyst. 102 There is strong evidence that oxidation of these C 2 and C 3 unsaturated hydrocarbons occurs via a direct, bimolecular surface reaction mechanism. Gabasch et al have studied ethene oxidation over Pd (111) by in situ XPS under lower oxygen partial pressures (1 Â 10 À3 mbar), conditions under which dissolved surface carbon shifts reaction selectivity towards CO above 480 K. 103 Oxidation of aromatics has also been studied by TP-FYNES over Pt (111), wherein oxydehydrogenation produces a range of surface intermediates.…”

Section: Hydrocarbon Combustionmentioning

confidence: 99%

Surface X-ray studies of catalytic clean technologies

2010

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The rational design of new heterogeneous catalysts for clean chemical technologies can be accelerated by molecular level insight into surface chemical processes. In situ methodologies, able to provide time-resolved and/or pressure dependent information on the evolution of reacting adsorbed layers over catalytically relevant surfaces, are therefore of especial interest. Here we discuss recent applications of surface X-ray techniques to surface-catalysed oxidations, (de)hydrogenations, C-C coupling, dehalogenation and associated catalyst restructuring, and explore how these may help to shape future sustainable chemistry.

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Comparisons of propylene and propyne catalytic oxidation on a 100 Å Pt/Al2O3 thin film using in situ soft X-ray fluorescence methods

Cited by 11 publications

References 24 publications

DFT study of propane dehydrogenation on Pt catalyst: effects of step sites

DFT study of propane dehydrogenation on Pt catalyst: effects of step sites

Operando X-ray absorption spectroscopy study of supported Pt catalysts during NO reduction by hydrocarbons

Surface X-ray studies of catalytic clean technologies

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