Catalytic activity and surface characteristics of layered Zn–Al–Si materials supported platinum

Saber, Osama; Gobara, Heba M.; Jaafari, Abdullah A. Al

doi:10.1016/j.clay.2010.12.026

Cited by 10 publications

(10 citation statements)

References 43 publications

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“…10 and Table 2. Result verification indicates that only benzene and hydrogen were the main products indicating that selectivity and conversion toward the dehydrogenation reaction is 100% at elevated temperatures of 450°C, and as previously reported when catalysts based on layered structure of Zn-Al-Si were utilized [18]. At lower temperatures of 250°C and 350°C, however, Pt/AS1 did not prove active towards the dehydrogenation reaction.…”

Section: Platinum-nano Catalysts Based On Silica-containing Alumina Nsupporting

confidence: 73%

“…Within the last ten years, unique properties of nano-structured materials have been revealed and many technological areas clearly stand to benefit from the development of materials on the nano-scale [18,19]. Dispersion and arrangement of nanoparticles in the alumina/silica oxide composites were important factors governing the hydrodesulphurization (HDS) reaction [20].…”

Section: Introductionmentioning

confidence: 99%

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Optimization of silica content in alumina-silica nanocomposites to achieve high catalytic dehydrogenation activity of supported Pt catalyst

Saber

Gobara

2014

Egyptian Journal of Petroleum

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The present work aims at obtaining a suitable and selective catalyst for catalytic dehydrogenation reactions through designing pore structures of silica-containing alumina nanocomposites by optimizing silica content in the structure. In this trend, series of silica-containing alumina nanocomposites with different molar ratios Al 2 O 3 /SiO 2 were prepared by the solvothermal method. According to surface characterization of silica-containing alumina nanocomposites, the sample with the highest molar ratio of Al 2 O 3 /SiO 2 (2.06) showed mesoporous structure with selective pore sizes of 3.7 and 4.6 nm. In addition, it had a high surface area value of 308 m 2 /g. Furthermore, SEM and TEM images of the same sample showed ultra fine sized particles in the nano size (7-17 nm). Dehydrogenation catalysts, as developed structures, were then achieved by loading 0.6 wt.% platinum metal over the prepared nanocomposites. Performances of the prepared nanocatalysts were investigated via the dehydrogenation of a model compound namely; cyclohexane. Experimental results showed that the Pt catalyst supported on the silica-containing alumina nanocomposites with the highest molar ratio of Al 2 O 3 /SiO 2 , is an efficient and selective catalyst toward the dehydrogenation reaction. This was revealed in terms of 100% selectivity of this catalyst toward the conversion of cyclohexane at all ranges of temperatures with the conversion reaction being temperature dependent. Practically, the total conversion of cyclohexane increased with increasing reaction temperature and reached 100% at 450°C while the prepared catalyst demonstrated absolute selectivity. ª 2014 Production and hosting by Elsevier B.V. on behalf of Egyptian Petroleum Research Institute.

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Section: Platinum-nano Catalysts Based On Silica-containing Alumina Nsupporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Optimization of silica content in alumina-silica nanocomposites to achieve high catalytic dehydrogenation activity of supported Pt catalyst

Saber

Gobara

2014

Egyptian Journal of Petroleum

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“…It revealed only one clear peak at 2θ=11.7° agreeing with the interlayered spacing (d 003 ) 0.76 nm. This peak is similar to the main peak of the conventional layered double hydroxides and the natural hydrotalcite ,…”

Section: Resultssupporting

confidence: 66%

“…X‐ray diffraction confirmed that nanoparticles of zinc oxide was formed and doped by three dopants; silicon, zirconium and titanium. Comparing with the crystals growth of the conventional LDHs,, Co‐Si‐Zr‐Ti LDH took long time for building its crystals. According to the reaction mechanism of urea hydrolysis and the experimental results, the important role of reaction time for building Co‐Si‐Zr‐Ti LDH could be explained.…”

Section: Discussionmentioning

confidence: 99%

Optimization Conditions for Crystal Growth of Novel Nanolayers, Nanohybrids and Nanocomposites Based on Cobalt, Zirconium, Titanium and Silicon

et al. 2019

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The present study has a triple aim for producing three novel nanostructures through incorporation of zirconium, titanium and silicon in the host layer of layered double hydroxides (LDH) beside cobalt. These four metals were designed in ordered structures for creating novel nanolayers inside LDH. By modifying these nanolayers with fatty acid, another novel nanohybrid material was produced. This nanohybrid contains 38% of inorganic species in addition to 62% of hydrocarbons fatty acid. In addition, the thermal treatment of the nanolayered structure converted the nanolayers of Co‐Si‐Zr‐Ti LDH to nanocomposites consisting of nanoparticles of cobalt oxide doped by triple dopants in an order manner: zirconium titanium and silicon. The crystals growth of Co‐Si‐Ti‐Zr LDH was studied from 9 h to 32 h through four stages. These stages were followed by different techniques. Finally, this study concluded that the nanolayered structure of Co‐Si‐Zr‐Ti, which is not yet published in the literature, could be formed with well‐crystallized phase. This novel 2D nanomaterial has positive impact to open the way for creating novel nanocomposites and nanohybrids.

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“…This may be acknowledged to the probable maximized hydrogen spillover effect under the applied experimental conditions. The % conversion of cyclohexane as well as the benzene yield (%) increased gradually with rising the reaction temperature and with the Pt loading, especially from 0.3 % to 0.6 % Pt content prepared by both reduction procedures [22][23][24]. This could be referred to the dispersion behavior of the optimized nanostructure of supported Pt particles; related mostly to the interaction profile of Pt species with surface hydroxyls of nanosilica support.…”

Section: In Cyclohexane Conversionmentioning

confidence: 94%

Can microwave assisted in situ reduction of supported Pt nanoparticles challenge the chemical method in controlling the dispersion profile-catalytic performance relationship?

et al. 2015

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In this study, Pt (of 0.3, 0.6 and 0.9 wt % loadings) was supported on mesoporous silica surface via microwave-assisted solution (MAS) method or rotary chemical evaporation (RCE) method in the in situ reduction step. The as-synthesized Pt nanocatalysts were characterized through XRD, XRF, TGA/ DSC, TEM, N 2 -adsorption-desorption, H 2 -pulse titration and electrical conductivity techniques. The samples prepared by MAS method exhibited higher surface area and a better dispersion profile of Pt NPs, of average sizes not exceeding 10 nm with increasing the Pt loading. In contrast, although RCE method showed higher efficacy in decomposing the used precursor, uneven distribution of larger Pt nanoparticles (≥ 33 nm) was displayed. Electrical properties in terms of AC conductivity and dielectric constant confirmed the enhancement of even distribution of smaller Pt NPs with higher concentration of grain boundaries affected by microwave electromagnetic radiations. Highly mobile electrons and lattice vibrations (phonons) were favored, as compared with aggregated NPs produced during RCE method. The TOF values calculated for reactions to selectively produce ethylene (from ethanol) or benzene (from cyclohexane) decreased with Pt loadings on catalyst samples synthesized by MAS method. The highly dispersed NPs (of 3-7 nm) seemed to be responsible of the activity in both reactions, tending probably to be structure insensitive. However, samples reduced by RCE method, with enlarged average sizes of surface Pt NPs (approaching 15.5 nm), exhibited increasing TOF values with Pt loading, i.e., turning the reactions most probably to be structure sensitive.

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Catalytic activity and surface characteristics of layered Zn–Al–Si materials supported platinum

Cited by 10 publications

References 43 publications

Optimization of silica content in alumina-silica nanocomposites to achieve high catalytic dehydrogenation activity of supported Pt catalyst

Optimization of silica content in alumina-silica nanocomposites to achieve high catalytic dehydrogenation activity of supported Pt catalyst

Optimization Conditions for Crystal Growth of Novel Nanolayers, Nanohybrids and Nanocomposites Based on Cobalt, Zirconium, Titanium and Silicon

Can microwave assisted in situ reduction of supported Pt nanoparticles challenge the chemical method in controlling the dispersion profile-catalytic performance relationship?

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