Catalytic dehydrogenation of propane to propene over platinum and platinum-gold alloys

doi:10.1016/0021-9517(77)90010-0

Journal of Catalysis

Volume 50, Issue 1, October 1977, Pages 77-86

https://doi.org/10.1016/0021-9517(77)90010-0 Get rights and content

Abstract

The rates of dehydrogenation of propane to propene over platinum and very dilute platinumin-gold alloys have been measured. In the composition range of 0.5–14.0 atom % platinum, the rates per unit surface area of the alloy powders vary linearly with the bulk platinum concentration in the alloys. From this it is concluded that only one platinum atom is involved in the rate-determining step.

For both platinum and the alloys, activation energies of some 29 ± 2 kcal/mole were measured. The reaction rate order in hydrogen, however, is different. It is proposed that propane dehydrogenation over platinum and over the alloys occurs via the same reaction mechanism, namely, dissociative chemisorption of propane on a single platinum atom to which two adsorption sites are associated, one of which carries a hydrogen atom. The subsequent conversion of the propyl radical into π-bonded propene via β-hydrogen elimination appears to be rate determining. The last step, desorption of π-bonded propene, has a comparatively low activation energy. The difference in negative reaction order, with respect to hydrogen, between platinum and its diluted alloys reflects a lower steady-state θ_H on Pt atoms surrounded by Au atoms vis-à-vis Pt atoms on a Pt surface.

References (25)

F.G. Gault et al.
J. Catal.
(1962)
V. Ponec et al.
J. Catal.
(1972)
J.H. Sinfelt et al.
J. Catal.
(1972)
J.J. Burton et al.
J. Catal.
(1975)
D.I. Hagen et al.
J. Catal.
(1976)
P. Pareja et al.
J. Catal.
(1975)
H. Verbeek et al.
J. Catal.
(1976)
J.J. Stephan et al.
J. Catal.
(1976)
J.R.H. Van Schaik et al.
J. Catal.
(1975)
P. Cossee
J. Catal.
(1964)

A. Takeuchi et al.

J. Catal.

(1975)

F.J. Kuijers et al.

J. Catal.

(1974)

Cited by (193)

Pt-based catalysts for direct propane dehydrogenation: Mechanisms revelation, advanced design, and challenges
2024, Molecular Catalysis
Heterogeneous catalytic dehydrogenation of propane to produce propylene (PDH) has been considered an efficient technique in the olefins supply chains. Metallic Pt is recognized as a promising catalyst for PDH reaction on account of its excellent affinity to CH bonds and CH activation ability. However, monometallic Pt catalysts usually exhibit an unsatisfactory performance (poor selectivity toward propylene and low catalytic stability), which is attributed to the severe sintering of Pt particles and the coke formation during the dehydrogenation process. Various metal promoters (M) are ingeniously introduced into Pt-based catalysts functioning via the formation of Pt-M alloys and/or intermetallics. Besides, several supports suitable for Pt-based catalysts have been probed to achieve high Pt dispersion and strong metal-support interaction. In this review, we precede the introduction of promoters and supports applied in Pt-based catalysts with an overview of PDH reaction mechanism. The specific roles of the promoter addition along with the advantages and drawbacks of state-of-art supports are significantly highlighted. Current challenges and prospects for the future development of Pt-based catalysts are also discussed.
A mini review on oxidative dehydrogenation of propane over boron nitride catalysts
2023, Petroleum Science
Oxidative dehydrogenation of propane is an attractive route for the synthesis of propylene due to its favorable thermodynamic and kinetic characteristics, however, it is challenging to realize high selectivity towards propylene. Recently, it has been discovered that boron nitride (BN) is a promising catalyst that affords superior selectivity towards propylene in oxidative dehydrogenation of propane. Summarizing the progress and unravelling the reaction mechanism of BN in oxidative dehydrogenation of propane are of great significance for the rational design of efficient catalysts in the future. Herein, in this review, the underlying reaction mechanisms of oxidative dehydrogenation of propane over BN are extracted; the developed BN catalysts are classified into pristine BN, functionalized BN, supported BN and others, and the applications of each category of BN catalysts in oxidative dehydrogenation of propane are summarized; the challenges and opportunities on oxidative dehydrogenation of propane over BN are pointed out, aiming to inspire more studies and advance this research field.
Effect of potassium and platinum contents on catalytic performance of Pt/Al<inf>2</inf>O<inf>3</inf> monometallic catalysts for propane dehydrogenation
2022, Molecular Catalysis
Low-loaded Pt-based catalysts supported on γ-Al₂O₃ (bare or modified by K) were studied for propane dehydrogenation. The alumina support was modified by adding 0.5 and 4 wt.% of K using potassium acetate as precursor. 0.5 wt.% of K is sufficient for suppressing the acidity of the alumina. Ultradispersed Pt supported catalysts (0.1, 0.2 and 0.3 wt.%) were obtained by ion exchange on Al₂O₃ or Al₂O₃–0.5 K. During propane dehydrogenation reaction, 0.3 wt.%Pt/Al₂O₃ strongly deactivates, mainly due to coke deposition. For the same Pt loading, the presence of K strongly decreases this phenomenon without modifying the initial turnover frequencies (TOF). On the series supported on Al₂O₃–0.5 K, there is no effect of the Pt content on the TOF values showing that whatever the sample, ultradispersed Pt entities present the same activity. Finally, the selectivity towards propene formation strongly depends on propane conversion and seems to be not affected by the change in K and Pt contents.
Sodium-free synthesis of mesoporous zeolite to support Pt-Y alloy nanoparticles exhibiting high catalytic performance in propane dehydrogenation
2021, Journal of Catalysis
Mesoporous zeolite-supported Pt₃Y catalyst deactivates slowly in propane dehydrogenation, maintaining high propane conversion and propylene selectivity, but the formation of the intermetallic compound requires atomistic migration of yttrium through silanol nests on the zeolite. Compared to the cumbersome generation of silanols via framework demetallation, we report a direct synthesis of mesoporous MFI zeolite possessing silanol nests. The synthesis procedure employed a diammonium-type bromide surfactant [C₁₈H₃₇N(CH₃)₂C₆H₁₂N(CH₃)₂C₄H₉Br₂] and a sodium-free silica source. The basicity of the synthesis mixture was adjusted by the addition of readily available N(CH₃)₄OH, instead of converting the surfactant to hydroxyl form. The presence of silanol nests in the resultant zeolite was confirmed by IR and NMR spectroscopies. When the zeolite was supported with 0.50 wt% Pt and 0.50 wt% Y using nitrate precursors, a remarkably long catalytic lifetime of 20 days was obtained with high propane conversion and propylene selectivity under the reaction condition using neat propane gas at 853 K.
Preparation of aluminum magnesium oxide by different methods for use as PtSn catalyst supports in propane dehydrogenation
2020, Catalysis Today
Various magnesium aluminum oxides [Mg(Al)O] were prepared by physical mixing, hydrothermal, and solvothermal method (with and without calcination) and employed as supports for bimetallic PtSn catalysts for propane dehydrogenation. The use of non-calcined Mg(Al)O-sv obtained from the solvothermal method led to the highest Pt dispersion, the lowest fraction of strong acid sites, and the lowest metallic tin species as well as coke content. Unlike the other catalysts that gradually deactivated with time-on-stream, the PtSn/Mg(Al)O-sv maintained high propylene yield ˜26.9% during 5 h reaction time without any sign of catalyst deactivation. The improved catalyst performances were attributed not only to the high surface area flower-like nanosheet structure of the Mg(Al)O-sv but also the uniform Mg-O-Al bonding and high Al/Mg atomic ratio on the catalyst surface as confirmed by the XPS results.
Fabrication of highly dispersed Pt-based catalysts on γ-Al<inf>2</inf>O<inf>3</inf> supported perovskite Nano islands: High durability and tolerance to coke deposition in propane dehydrogenation
2019, Applied Surface Science
Citation Excerpt :
However, coke deposition and sintering of active components still are adverse factors to the activity of PDH [14–17]. Fortunately, it has been proved that the single atom Pt-based active sites are beneficial for the PDH reaction [18]. Although there are some reports about supported atomic-scale metallic catalysts, it is still difficult to keep these single metal atoms durable and atomically dispersed status under high temperature reaction [19,20].
A series of novel γ-Al₂O₃ supported PtIn bimetallic catalysts were prepared by perovskite (PTO) lattice interstitial confined reduction and compared with industrial catalyst PtIn/γ-Al₂O₃ in the propane dehydrogenation to propene. The physics-chemistry properties of all catalysts and precursors were characterized by BET, NH₃-TPD, TPR, XRD, TEM, STEM-EDS, XPS, TG and O₂-TPO techniques. The results show that the metal ions of Pt⁴⁺ and In³⁺ confined in PTO lattice interstitial sites were more easily reduced than those confined in PTO lattice. The lattice interstitial confinement was beneficial for the formation of small and highly dispersed PtIn bimetallic species on the surface of γ-Al₂O₃ supported PTO Nano islands. It is just the confinement of PTO lattice interstitial sites for appropriate In³⁺/In⁰ ratio and weak PtIn interaction and the sharing AlO bond for anchoring PTO nanoparticles and weakening the surface acid sites result in the high activity and superior stability of PtIn/LaAlO₃/γ-Al₂O₃ in propane dehydrogenation. The initial propane conversion of PtIn/LaAlO₃/γ-Al₂O₃ was 47%, and can be maintained at 25% after 16 h, while its propene selectivity only decreased from 96% to 90%.

View all citing articles on Scopus

View full text