Propane combustion over Pt/Al2O3 catalysts with different crystalline structures of alumina

Park, Jung Eun; Kim, Bo Bae; Park, Eun Duck

doi:10.1007/s11814-015-0062-6

Cited by 30 publications

(8 citation statements)

References 35 publications

(53 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The TPR peak position, area and its intensity are related to the reducibility and amount of reducible species on the catalyst. 52 In Figure 5g, the ZnO and PdRh HC/ZnO exhibit one highest hydrogen consumption peaks at 501 and 518 °C, respectively, which is assigned to the reduction of ZnO to metallic zinc. Moreover, compared with ZnO, the highest peak of PdRh HC/ZnO was shifted to a slightly higher temperature, indicating that PdRh HC/ZnO is more difficult to be reduced than ZnO.…”

Section: Resultsmentioning

confidence: 94%

“…To further understand the effect of PdRh bimetal addition on the redox performance of the sensing materials, the ZnO and PdRh HC/ZnO were characterized by H 2 temperature program reduction (H 2 –TPR), as shown in Figure g. The TPR peak position, area and its intensity are related to the reducibility and amount of reducible species on the catalyst . In Figure g, the ZnO and PdRh HC/ZnO exhibit one highest hydrogen consumption peaks at 501 and 518 °C, respectively, which is assigned to the reduction of ZnO to metallic zinc.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

High-Sensitive MEMS Hydrogen Sulfide Sensor made from PdRh Bimetal Hollow Nanoframe Decorated Metal Oxides and Sensitization Mechanism Study

Luo

Chen

Zhang

et al. 2020

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

Here we report the fabrication of a high performance metal oxide semiconductor (MOS) sensor for the detection of hydrogen sulfide (H 2 S) using PdRh bimetal hollow nanocube (HC) with Rh-rich hollow frame and Pd−rich core frame as sensitizing materials. PdRh bimetal HC with the edge-length about 10 nm was prepared by chemical etching PdRh bimetal solid nanocube (SC) in HNO 3 aqueous solution. The results of gas-sensing tests indicate that the response value order of the MEMS gas sensors based on MOSs (including ZnO, MoO 3 and SnO 2 ) is as follows: R PdRh HC/MOS > R PdRh SC/MOS > R MOS . First, in the system of ZnO, gas sensor modified by PdRh (PdRh SC/ZnO and PdRh HC/ ZnO) possess enhanced H 2 S sensing performance with a better response and excellent lowconcentration detection capability (down to 15 ppb) comparing to pure ZnO. The improved H 2 S sensing performance could be attributed to the good conductivity of Rh−rich frame, the high catalytic activity of PdRh bimetal and formation of Schottky barrier-type junctions and defect. Second, PdRh HC/ZnO sensor shows better response (185-1 ppm of H 2 S) compared to PdRh SC/ZnO sensor (108-1 ppm of H 2 S), which is due to the higher specific surface area of PdRh HC/ZnO and good gas diffusion of the hollow structure. This work indicate that the sensitization characteristics of PdRh bimetal HC will provide new paradigms for the future development of the high performance sensor.

show abstract

Section: Resultsmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 99%

High-Sensitive MEMS Hydrogen Sulfide Sensor made from PdRh Bimetal Hollow Nanoframe Decorated Metal Oxides and Sensitization Mechanism Study

Luo

Chen

Zhang

et al. 2020

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

show abstract

“…Assuming metallic Pt being the active phase, many claim that support acidity increases platinum resistance to oxidation, as Pt on acidic supports was claimed to be less oxidized according to X-ray photoelectron spectroscopy (XPS) and in situ X-ray absorption near-edge structure (XANES) analysis. ,, In other works, support acidity was suggested to play a role in helping Pt dissociate the C–H bond by the pair of metallic Pt 0 and partially oxidized Pt δ+ or Pt δ+ and acidic WO x clusters in tungsten-promoted catalysts . Even more, since propane combustion is structure-sensitive, , acid-treated supports were found to increase metal dispersion, thus indicating that this aspect is responsible for promoted activity and thermal stability . However, opposite claims were also made. , These contradictory trends might be caused by inconsistent changes in variables, because conventional catalyst preparation methods lead to uncontrolled catalyst structures, especially in terms of Pt particle size.…”

Section: Introductionmentioning

confidence: 99%

Support Acidity Improves Pt Activity in Propane Combustion in the Presence of Steam by Reducing Water Coverage on the Active Sites

Yang

Zhu

et al. 2021

ACS Catal.

View full text Add to dashboard Cite

Support effects in catalysis are important in determining the catalytic activity of supported phases through geometric and electronic effects. Unveiling and quantifying support effects lead to the opportunity to finely tune and optimize the activity of supported catalysts. The study of support effects needs to be conducted in conditions where other important parameters, such as size and composition of the active phase, are not influencing the activity. This requirement is particularly important when the activity is affected by reactants or products that have implications in the reaction mechanism, as is the case of water in hydrocarbon combustion. Here, we present a systematic study on the effects of support acidity and water on propane combustion catalyzed by platinum-based catalysts that reveal support effects beyond the conventional geometric and electronic effects. A set of catalysts prepared from colloidal Pt nanoparticles supported on alumina, silica–alumina, and tungsten oxide-modified silica–alumina with increasing controlled Brønsted acid site density was prepared. We observed a monotonic increase in reaction rate as the same Pt particles were supported on progressively more acidic supports, with an improvement of up to 40 times in reaction rate for the sample with the highest Brønsted acid site density [Pt/WO3(10%)/30% SiO2/Al2O3] compared to the bare Pt/Al2O3 sample. Based on kinetic measurements on samples with different Pt particle sizes, we propose that (i) the metal–support perimeter participates in the reaction, and (ii) the interaction between metal and Brønsted acid sites is responsible for the increase in activity. The origin of such rate increase was found to be related to the enhanced resistance to water poisoning introduced by the acid sites: samples with higher acidity displayed nearly zero water rate order and more stable rates in the presence of steam. Using a Langmuir–Hinshelwood model, the most acidic sample was shown to display the lowest water coverage on the Pt surface. Summarizing all the observations, we propose that the Brønsted acid sites help reduce water coverage on the Pt surface through a spillover-like mechanism, which results in available sites for propane adsorption and activation and thus higher reaction rates in propane combustion. This work highlights how supports play a role not only in modifying electronic and geometric properties of supported phases, but also in the reaction mechanism through active roles in modifying surface coverages.

show abstract

“…H 2 -TPR profiles showed broad and intense peaks at temperatures between 100 and 200 • C and small peaks at temperatures between 300 and 500 • C (see Figure 7). The first broad peaks were due to the reduction of PtO and PtO 2 species weakly bonded to the surface of the support [28]. The second peak indicated strong support interaction with Pt, possibly leading to the formation of PtAl 2 O 4 spinel species (formed during impregnation and calcination), which are difficult to reduce.…”

Section: Hydrogen Temperature-programmed Reduction (H 2 -Tpr)mentioning

confidence: 99%

The Effect of Mg and Zn Dopants on Pt/Al2O3 for the Dehydrogenation of Perhydrodibenzyltoluene

et al. 2021

View full text Add to dashboard Cite

The effects of Mg and Zn dopants on the catalytic performance of Pt/Al2O3 catalyst were investigated for dehydrogenation of perhydrodibenzyltoluene (H18-DBT) as a liquid organic hydrogen carrier. Al2O3 supports were modified with Mg and Zn to produce Mg-Al2O3 and Zn-Al2O3 with a target loading of 3.8 wt.% for dopants. The modified supports were impregnated with chloroplatinic acid solution to produce the catalysts Pt/Al2O3, Pt/Mg-Al2O3 and Pt/Zn-Al2O3 of 0.5 wt.% Pt loading. Thereafter, the catalysts were characterised using inductively coupled plasma- optical emission spectrometry, scanning electron microscopy-energy dispersive X-ray spectroscopy, hydrogen temperature-programmed reduction, carbon-monoxide pulse chemisorption, ammonia temperature-programmed desorption, X-ray diffraction and transmission electron microscopy. The dehydrogenation experiments were performed using a horizontal plug flow reactor system and the catalyst time-on-stream was 22 h. Pt/Mg-Al2O3 showed the highest average hydrogen flowrate of 29 nL/h, while an average of 27 nL/h was obtained for both Pt/Al2O3 and Pt/Zn-Al2O3. This has resulted in a hydrogen yield of 80% for Pt/Mg-Al2O3, 71% for Pt/Zn-Al2O3 and 73% for Pt/Al2O3. In addition, the conversion of H18-DBT ranges from 99% to 92%, Pt 97–90% and 96–90% for Pt/Mg-Al2O3, Pt/Zn-Al2O3 and Pt/Al2O3, respectively. Following the latter catalyst order, the selectivity to dibenzyltoluene (H0-DBT) ranges from 78% to 57%, 75–51% and 71–45%. Therefore, Pt/Mg-Al2O3 showed improved catalytic performance towards dehydrogenation of H18-DBT.

show abstract

Propane combustion over Pt/Al2O3 catalysts with different crystalline structures of alumina

Cited by 30 publications

References 35 publications

High-Sensitive MEMS Hydrogen Sulfide Sensor made from PdRh Bimetal Hollow Nanoframe Decorated Metal Oxides and Sensitization Mechanism Study

High-Sensitive MEMS Hydrogen Sulfide Sensor made from PdRh Bimetal Hollow Nanoframe Decorated Metal Oxides and Sensitization Mechanism Study

Support Acidity Improves Pt Activity in Propane Combustion in the Presence of Steam by Reducing Water Coverage on the Active Sites

The Effect of Mg and Zn Dopants on Pt/Al2O3 for the Dehydrogenation of Perhydrodibenzyltoluene

Contact Info

Product

Resources

About