Structural analysis of a Pt Pd core-shell/Al-SBA-15 catalyst synthesized by the solid-state impregnation route

Medina-Mendoza, A.K.; Ángeles–Chávez, C.; Cortés-Jácome, M.A.; Toledo-Antonio, J.A.

doi:10.1016/j.matchemphys.2019.02.069

Cited by 9 publications

(23 citation statements)

References 32 publications

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“…These off-center core positions are however metastable, so that they evolve at a later stage into intermixed configurations, that are initially somewhat asymmetric, and then progressively become symmetric. Pt@Pd nanoparticles with off-center cores have been observed in several experiments, 15,[17][18][19]25,43 which support the long-lifetime metastability of these configurations.…”

Section: Discussionmentioning

confidence: 76%

“…Pt@Pd and (PtPd)@Pd nanoparticles with off-center cores have been observed in several experiments. 15,[17][18][19]25,43 In these experiments, the nanoparticles have been grown in isotropic environments, so that the cause of the symmetry breaking leading to the off-center cores is not obvious. The mechanism revealed by our simulations could explain why these structures form, along with their long-lasting metastability.…”

Section: Ptpdmentioning

confidence: 99%

“…10 In PtPd, a variety of Pt@Pd, Pd@Pt and intermixed structures have been synthesised in co-reduction and successive reduction experiments. [15][16][17][18][19][20][21] Other highly miscible systems in which core@shell nanoalloys have been obtained by wet-chemistry methods are AuPd and AuCu. 22,23 In gas-phase experiments, the formation of B-rich (AB)@B nanoalloys, where the minority element A is always concentrated at the center of the nanoparticle, has been observed in AgAu, PtPd and PtNi.…”

Section: Introductionmentioning

confidence: 99%

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Interplay between interdiffusion and shape transformations in nanoalloys evolving from core–shell to intermixed structures

2023

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Section: Discussionmentioning

confidence: 76%

Section: Ptpdmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Interplay between interdiffusion and shape transformations in nanoalloys evolving from core–shell to intermixed structures

2023

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“…However, SBA-15 has low acidity, so other materials must be added to its structure to improve its catalytic activity, such as organic functional groups, coordination compounds, metallic nanoparticles and metallic oxides [29,33]. The addition of these materials is facilitated by the high concentration of silanol groups (Si-OH) that promote strong interaction between the support and the ligand and function as active sites for the desired reactions [34].…”

Section: Introductionmentioning

confidence: 99%

Methods for Pt-WO3/SBA-15 materials synthesis for glycerol conversion

et al. 2023

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Glycerol has applications as a raw material in different industrial processes, however, its supply exceeds demand. An alternative to increase the added value of this feedstock is its conversion into high added-value chemical products through dehydration and hydrogenation reactions, from which 1,2-PDO and 1,3-PDO can be obtained. To develop catalysts that increase the conversion and selectivity of these processes, materials of 2% Pt and 10% WO 3 supported on SBA-15 were studied. Two methods were used for incipient wetness impregnation: sequential impregnation, with impregnation steps for each species, and co-impregnation, with a single impregnation step for both species. From the analysis of XRD, XRF, N 2 isotherms, SEM, EDS, FTIR, and pyridine FTIR spectroscopy, it was possible to observe the influence of these methods on the structural and textural properties. It was verified that the co-impregnation provided a better dispersion of the WO 3 species on the surface of the SBA-15 and that the reduction process, for both methodologies employed, showed an improvement in the metallic dispersion. The better dispersion of WO 3 species also resulted in a greater formation of Brønsted acid sites for the co-impregnation method, with a predominance of Lewis sites in the structure of the catalysts obtained by both methods.

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“…To incorporate metal oxide precursors into mesoporous materials, incipient wetness impregnation is one of the most widespread methods for its simplicity and because it ensures that practically all the active phase is located inside the mesopores. However, various authors have reported materials based on SBA-15 in which it is possible to obtain a good dispersion of the active material incorporating it via "solid impregnation" [31,[46][47][48]. For example, Tang et al [31] synthesized catalysts CuO-CeO2/SBA-15 using the solid impregnation and wet impregnation methods and found better catalytic results for the first alternative.…”

Section: Introductionmentioning

confidence: 99%

Study of CuO–CeO2 catalysts supported on ordered porous silica with different mesostructure and morphology. Influence on CO preferential oxidation

Lacoste

Tiscornia²,

Bonne³

et al. 2021

Microporous and Mesoporous Materials

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In the present work, SBA-15 and SBA-16 ordered mesoporous silicas were synthesized with different morphologies such as fibers, spheres, rods and irregular shapes. Copper and cerium oxides active phase was introduced by two methods, incipient wetness impregnation and solid-state impregnation by using a ball mill. The obtained catalysts were evaluated in the 2 CO preferential oxidation reaction (COPrOx). By means of SAXS, XRD, SEM and TEM microscopies, the mesostructures and morphologies were characterized, as well as the preservation of the porous structure and the presence of oxides nanoparticles. In addition, XPS spectroscopy was used to analyze the chemical state and relative surface abundance of the elements present in the catalysts. From the catalytic results, it could be seen that the incipient wetness impregnation method was the most favorable. The unidirectional porous structure SBA-15 with fiber shape and incipient wetness impregnation achieved the highest conversion of CO and selectivity to CO2 (CO conversion 98 % at 175 °C). SBA-16 based catalysts were found less active. However, it is noteworthy that the best material was prepared by using an irregular shaped SBA-16 impregnated by incipient wetness procedure. This catalyst exhibited a maximum CO conversion of 80 % at 175 °C. Finally, the SBA-15 mesoporous structure and the incipient wetness impregnation method had a greater influence on the better catalytic performance.

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Structural analysis of a Pt Pd core-shell/Al-SBA-15 catalyst synthesized by the solid-state impregnation route

Cited by 9 publications

References 32 publications

Interplay between interdiffusion and shape transformations in nanoalloys evolving from core–shell to intermixed structures

Interplay between interdiffusion and shape transformations in nanoalloys evolving from core–shell to intermixed structures

Methods for Pt-WO3/SBA-15 materials synthesis for glycerol conversion

Study of CuO–CeO2 catalysts supported on ordered porous silica with different mesostructure and morphology. Influence on CO preferential oxidation

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