Insights into catalyst structure, kinetics and reaction mechanism during propane dehydrogenation on Pt-Ge bimetallic catalysts

Rimaz, Sajjad; Kosari, Mohammadreza; Chen, Luwei; Xi, Shibo; Μοnzόn, A.; Kawi, Sibudjing; Borgna, Armando

doi:10.1016/j.apcata.2022.118751

Cited by 13 publications

(13 citation statements)

References 46 publications

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“…For the Co@MFI-B130 catalyst, n [H 2 ] is almost 0, while it decreases to −0.12 with a thinner thickness. Reaction with the first dehydrogenation as the rate-determining step exhibits n [H 2 ] close to 0. , The mechanism of the PDH reaction over different CoO sites in the MFI framework was subsequently investigated through DFT calculations (Figure c). First, H • would be captured by an O atom adjacent to the Lewis CoO site to form Co–C 3 H 7 *, thus achieving the activation of propane molecules and cleavage of the heterolytic C–H bond.…”

Section: Resultsmentioning

confidence: 99%

Boosting Propane Dehydrogenation by the Regioselective Distribution of Subnanometric CoO Clusters in MFI Zeolite Nanosheets

Yang

Song

et al. 2023

ACS Appl. Mater. Interfaces

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Direct dehydrogenation of propane (PDH) has already been implemented worldwide in industrial processes to produce value-added propylene. The discovery of earth-abundant and environmentally friendly metal with high activity in C−H cleavage is of great importance. Co species encapsulated within zeolite are highly efficient for catalyzing direct dehydrogenation. However, exploring a promising Co catalyst remains a nontrivial target. Direct control of the regioselective distribution of Co species in the zeolite framework through altering their crystal morphology gives opportunities to modify the metallic Lewis acidic features, thus providing an active and appealing catalyst. Herein, we achieved the regioselective localization of highly active subnanometric CoO clusters in straight channels of siliceous MFI zeolite nanosheets with controllable thickness and aspect ratio. The subnanometric CoO species were identified by different types of spectroscopies, probe measurements, and density functional theory calculations, as the coordination site for the electron-donating propane molecules. The catalyst showed promising catalytic activity for the industrially important PDH with propane conversion of 41.8% and propylene selectivity higher than 95% and was durable during 10 successive regeneration cycles. These findings highlight a green and facile method to synthesize metal-containing zeolitic materials with regioselective metal distribution and also to open up a future perspectives for designing advanced catalysts with integrated advantages of the zeolitic matrix and metal structures.

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Section: Resultsmentioning

confidence: 99%

Boosting Propane Dehydrogenation by the Regioselective Distribution of Subnanometric CoO Clusters in MFI Zeolite Nanosheets

Yang

Song

et al. 2023

ACS Appl. Mater. Interfaces

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“…Although the local temperature cannot be measured in our system, the above kinetic results together indicate the presence of the nonthermal effect. The nonthermal effect could enhance C 3 H 8 activation by generating more V δ+ species (3 < δ < 5) …”

Section: Resultsmentioning

confidence: 99%

“…The nonthermal effect could enhance C 3 H 8 activation by generating more V δ+ species (3 < δ < 5). 34 For investigating the possible intermediate, in situ C 3 H 8 DRIFTS were recorded. An obvious V-C 3 H 5 vibration (Figure S11a) located at 1555 cm −1 appeared on 3V rather than pure TiO 2 (Figure S11b), which indicates the direct interaction between V atoms and C 3 H 8 molecules.…”

Section: Positive Effect Of Photon Injection On Activitymentioning

confidence: 99%

Photothermal Propane Dehydrogenation Catalyzed by VO_x-Doped TiO₂ Nanoparticles

Sun

et al. 2023

ACS Appl. Nano Mater.

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Propane direct dehydrogenation (PDH) has received much attention. How to effectively catalyze inert C–H bond activation is of great significance for industrial development. Pt-based catalysts show excellent activity but are limited by their expensive price. Cr-based catalysts are scarcely applied owing to their high toxicity. V-based catalysts are appropriate candidates for their cheap price and low toxicity, but they suffer from high energy consumption. The photothermal synergy effect induced by nonradiative relaxation is expected to make the C–H bond activation and hydrogen coupling process easier compared to bare thermal catalysis. Herein, a set of V/TiO2 nanoscale catalysts were synthesized. The optimized 3 wt % V/TiO2 catalyst (hereafter simplified as 3V) has a particle size of ∼26 nm, achieving a propylene production rate of 342 μmol·g–1·h–1 at 500 °C with UV–vis light radiation, which is 9.2% higher compared with bare thermal conditions. In situ radiation X-ray photoelectron spectroscopy (XPS) shows that photon injection leads to more electron-deficient V atoms (Vδ+, 5 > δ > 3). The strengthened Lewis acidity enhances the C3H8 activation as revealed by kinetic evidence and in situ C3H8-DRIFT measurements. The calculated molecular orbital diagrams show that the V atoms decrease the energy gap between the highest occupied orbital (HOMO) of C3H8 and the lowest unoccupied orbital (LUMO) of the model catalyst. This work describes an efficient photothermal synergy approach, specifically the nonthermal effect for promoting propane dehydrogenation.

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“…Ge, located in the same main group as Sn and Pb in the periodic table, has a similar valence electron configuration and a similar effect on enhancing the dehydrogenation activity of Pt-based catalysts for alkane dehydrogenation. − Ballarini et al studied the dehydrogenation behaviors of n -butane and n -decane over the Sn-modified Pt-based catalyst and the Ge-modified Pt-based catalyst, and a small electronic interaction and a surface segregation of Sn were observed on the PtSn catalyst, while strong Pt–Ge alloys were formed on the PtGe catalyst. , Jimenez-Izal’s groups have proved the fact that the optimizing principles of Ge were traced back to both geometric and electronic effects with the aid of PW-DFT calculations and the PBE functional . Subsequently, Rimaz and their team investigated the promoting effect of Ge on Pt-based catalysts for propane dehydrogenation and further optimized the dehydrogenation performance over the Pt–Ge bimetallic catalyst. − , In summary, with regard to the geometric aspect, sintering of Pt species by Ostwald ripening was halted due to the formation of Pt x Ge y alloy after introducing Ge species, which inhibits the deeper dehydrogenation to coke; as a result, the selectivity to desired olefins was raised along with an improved catalyst stability. The electronic aspect can be interpreted by the occurrence of electron transfer from Ge to Pt, leading to a saturation of unpaired electrons required for the activation of alkenes, thereby improving the desired olefin selectivity without sacrificing alkane conversion.…”

Section: Introductionmentioning

confidence: 99%

Novel Ge/SiO₂ Catalysts for Nonoxidative Dehydrogenation of Propane

Zhang,

Ma,

Zhao

et al. 2024

Energy Fuels

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This paper reports for the first time that the Ge/ SiO 2 catalyst can also exhibit dehydrogenation activity for propane dehydrogenation. This finding breaks our traditional wisdom about the part of Ge species playing in dehydrogenation of light alkanes. The study proves that metallic Ge and Ge suboxide species (such as Ge 2+ ) are regarded as the active species for propane dehydrogenation instead of a promoter for noble metal catalysts. These active Ge species can be formed during dehydrogenation reaction, and the formation rate can be accelerated through reduction pretreatment. Notably, the dispersion of the active Ge species does have a significant effect on the dehydrogenation performance, and the agglomeration of the active Ge species caused by the over-reduction leads to a fast deactivation of the Ge/SiO 2 catalyst.

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Insights into catalyst structure, kinetics and reaction mechanism during propane dehydrogenation on Pt-Ge bimetallic catalysts

Cited by 13 publications

References 46 publications

Boosting Propane Dehydrogenation by the Regioselective Distribution of Subnanometric CoO Clusters in MFI Zeolite Nanosheets

Boosting Propane Dehydrogenation by the Regioselective Distribution of Subnanometric CoO Clusters in MFI Zeolite Nanosheets

Photothermal Propane Dehydrogenation Catalyzed by VO_x-Doped TiO₂ Nanoparticles

Novel Ge/SiO₂ Catalysts for Nonoxidative Dehydrogenation of Propane

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Insights into catalyst structure, kinetics and reaction mechanism during propane dehydrogenation on Pt-Ge bimetallic catalysts

Cited by 13 publications

References 46 publications

Boosting Propane Dehydrogenation by the Regioselective Distribution of Subnanometric CoO Clusters in MFI Zeolite Nanosheets

Boosting Propane Dehydrogenation by the Regioselective Distribution of Subnanometric CoO Clusters in MFI Zeolite Nanosheets

Photothermal Propane Dehydrogenation Catalyzed by VOx-Doped TiO2 Nanoparticles

Novel Ge/SiO2 Catalysts for Nonoxidative Dehydrogenation of Propane

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Photothermal Propane Dehydrogenation Catalyzed by VO_x-Doped TiO₂ Nanoparticles

Novel Ge/SiO₂ Catalysts for Nonoxidative Dehydrogenation of Propane