In Situ Characterization of Sn–Pt/SiO2 Catalysts Used in Low Temperature Oxidation of CO

Margitfalvi, József L.; Borbáth, Irina; Lázár, K.; Tfirst, E.; Szegedi, Ágnes; Hegedűs, Mihály; Gőbölös, S.

doi:10.1006/jcat.2001.3237

Cited by 56 publications

(48 citation statements)

References 27 publications

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“…It is known that Sn can be reduced easily only in the very near neighborhood of Pt, during which formation of Sn-Pt alloys may take place [57,58]. The ratio of the surface metallic Sn to surface total Sn content after the in situ reduction was in the range of 19-25 % in every Sn containing sample of this work.…”

Section: Insert Figure 11mentioning

confidence: 63%

“…This thin coating is supposed to be tinoxide. As we mentioned above, SnO x can only be reduced at relative mild conditions if it is in intimate contact with Pt [57,58] thus we suppose that some part of the Pt containing nanoparticles was covered by SnO x in the sample SnOx-I Pt H2 red (and in the used one). Our in situ reduction experiments suggested Sn-Pt alloy formation even in the case of the calcined SnOx-I Pt samples, while it is well established that oxidation of Sn-Pt alloys results in extensive segregation of tin oxide onto the surface [62] especially in nanosized systems [63].…”

Section: Insert Figure 12mentioning

confidence: 89%

“…Thus the thin SnO x on the top of Pt-containing nanoparticles could form easily and quickly via migration of tin to the surface and stabilization there in the form of tin-oxide [57,58] when supported Sn-Pt alloy nanoparticles are exposed to air during the handling. When the surface concentration of Sn is high enough and the cocatalyst is formed by high temperature hydrogen treatment, the amount of the formed Sn-Pt alloy can be significant.…”

Section: Insert Figure 12mentioning

confidence: 99%

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PtOx-SnOx-TiO2 catalyst system for methanol photocatalytic reforming: Influence of cocatalysts on the hydrogen production

et al. 2018

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Abstract:Effects of modification of PtO x -TiO 2 photocatalysts by tin were elucidated by exploring relationships between the structural properties of variously prepared tin-loaded catalysts and their catalytic activity in methanol photocatalytic reforming. Tin free and amorphous tinoxide decorated TiO 2 samples were prepared by sol-gel method from titanium-isopropoxide.In other approach, Sn was loaded onto the sol-gel prepared TiO 2 by impregnation followed by calcination. Pt was introduced by impregnation followed by either reduction in H 2 at 400 o C or calcination at 300 o C. TEM, XRD and Raman spectroscopic measurements proved that TiO 2 existed in the form of aggregates of polycrystalline anatase with primary particle size of 15-20 nm in each of the samples. Photocatalytic hydrogen production was influenced by the combined effect of many parameters. Both the presence of Sn and the way of Pt co-catalyst formation played important role in the activity of these photocatalysts. The Sn introduction by both sol-gel method and impregnation clearly enhanced the photocatalytic activity.

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Section: Insert Figure 11mentioning

confidence: 63%

Section: Insert Figure 12mentioning

confidence: 89%

Section: Insert Figure 12mentioning

confidence: 99%

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PtOx-SnOx-TiO2 catalyst system for methanol photocatalytic reforming: Influence of cocatalysts on the hydrogen production

et al. 2018

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“…From this dependence the recoilless fraction and the strengths of bond of the components could also be proposed. From these considerations we have concluded that the reversibly formed Sn 4+ component is not bonded to the oxide support, instead, it is still on the surface of metallic particles [8].…”

Section: Low Temperature Oxidation Of Co -Ptsn/sio 2 Catalystmentioning

confidence: 85%

Environmental applications: catalysts and removal or re-cycling of by products

Lázár¹

2011

Hyperfine Interact

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Some applications of Mössbauer spectroscopy are presented with environmental implications. In particular, catalytic processes are discussed with examples for catalyst immobilisation, for removal of contaminants and for decomposition of harmful compounds. Examples are also presented for processes of recycling of end products. Keywords Environmental applications · Catalysts · Recycling of by products CatalystsMössbauer spectroscopy may successfully contribute to study of catalysts [3]. Most of these studies are related to in situ characterization of solid supported catalysts. Three

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“…Based on CSRs a new method was developed for the preparation of different types of supported E x -M y (E= Sn, Ge; M= Pt, Pd, Rh, Ru) catalysts with exclusive formation of metal-metal interaction and high E/M ratios [12][13][14]. Catalysts prepared in this way showed unique properties in variety of reactions (CO oxidation, naphtha reforming, selective hydrogenation and dehydrogenation of organic compounds [15][16][17][18][19]). …”

mentioning

confidence: 99%

CO oxidation and oxygen reduction activity of bimetallic Sn–Pt electrocatalysts on carbon: effect of the microstructure and the exclusive formation of the Pt3Sn alloy

Gubán

Tompos

Bakos

et al. 2017

Reac Kinet Mech Cat

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Electronic supplementary material:The online version of this article (doi: 10.1007/s11144-017-1152-8) contains supplementary material, which is available to authorized users. Abstract Alloy-type Sn-Pt/C electrocatalysts with desired Pt/Sn= 3.0 ratio have been prepared by Controlled Surface Reactions using home-made 20 wt.% Pt/C (20Pt/C) catalysts with different Pt dispersion. Reaction conditions were found for the preparation of highly dispersed 20Pt/C catalysts by modified NaBH 4 -assisted ethylene-glycol reduction method using ethanol as a solvent. It has been demonstrated that the increase of the heating time in ethanol up to 2 h results in decreasing dispersion of Pt. Upon using highly dispersed 20Pt/C catalyst the exclusive incorporation of Sn onto the Pt sites was achieved resulting in exclusive formation of the Pt-Sn alloy phase. According to in situ XPS studies pre-treatment of the air exposed catalyst in H 2 even at 170°C resulted in complete reduction of the ionic tin to Sn 0 , suggesting alloy formation. In contrast, the catalyst with lower Pt dispersion cannot be completely reduced even at 350°C, as 10 % of tin still remains in the form of Sn 4+ surface species. The electrocatalytic performance of both Sn-20Pt/C catalysts in the CO electrooxidation and the oxygen reduction reaction is superior to that of the parent 20Pt/C catalysts. Our data obtained for the oxygen reduction reaction indicate that the small size of the bimetallic nanoparticles in the highly dispersed Sn-20Pt/C catalyst, along with their optimal surface composition, result in increased activity compared to the catalyst with lower dispersion.Keywords SnPt/C electrocatalysts, Controlled surface reactions, Pt 3 Sn, Oxygen reduction reaction, CO electrooxidation IntroductionPolymer electrolyte membrane fuel cells (PEMFC) offer a very promising solution for environmentally sustainable electric power generation in mobile applications. A major challenge in PEMFC development is the choice of the cathode and anode electrocatalysts, which usually consist of platinum supported on carbon. The Pt/C system is, however, prone to corrosion at high potentials occurring during rapid load change conditions, and sensitive to poisoning by CO, which is a common low level impurity of the hydrogen fuel. As a result, electrocatalysts with acceptable lifetime can only be manufactured with very high Pt loadings. Therefore, a main development goal is to find electrocatalysts with reduced Pt content, enhanced long term stability under operating conditions and affordable price. CO tolerance of the anode electrocatalysts also has to be improved, as CO adsorbs very strongly on Pt, blocking the active sites for the hydrogen oxidation reaction and causing a large decrease in the electrode performance. In order to reduce this poisoning issue, a common approach consists of the utilization of a second oxophilic metal such as Ru, Mo, Ni or Sn [1][2][3][4][5], which are less noble than Pt and thus activate water at lower potential leading to accelerated CO 2

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In Situ Characterization of Sn–Pt/SiO2 Catalysts Used in Low Temperature Oxidation of CO

Cited by 56 publications

References 27 publications

PtOx-SnOx-TiO2 catalyst system for methanol photocatalytic reforming: Influence of cocatalysts on the hydrogen production

PtOx-SnOx-TiO2 catalyst system for methanol photocatalytic reforming: Influence of cocatalysts on the hydrogen production

Environmental applications: catalysts and removal or re-cycling of by products

CO oxidation and oxygen reduction activity of bimetallic Sn–Pt electrocatalysts on carbon: effect of the microstructure and the exclusive formation of the Pt3Sn alloy

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