Bimetallic PtSn catalyst for selective CO oxidation in H2-rich gases at low temperatures

Schubert, Markus M.; Kahlich, M.J.; Feldmeyer, G.J.; Hüttner, M.; Hackenberg, Stefan; Gasteiger, Hubert A.; Behm, R. Jürgen

doi:10.1039/b008062o

Cited by 164 publications

(145 citation statements)

References 47 publications

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“…Catalyst formulations found to be active in the PROX reaction can be classified as: gold based catalysts [5][6][7][8], supported Pt [5,[8][9][10][11][12], Rh [9], Ru [9,13], and bimetallic Pt-Sn [11,14] and other systems not containing metallic phase, such as CuO/CeO 2 [5,15]. These systems, as a rule, are also active in the low temperature CO oxidation.…”

Section: Introductionmentioning

confidence: 99%

Preferential CO oxidation in hydrogen (PROX) on ceria-supported catalysts, part II: Oxidation states and surface species on Pd/CeO2 under reaction conditions, suggested reaction mechanism

Pozdnyakova

Teschner

Wootsch

et al. 2006

Journal of Catalysis

205

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The aim of the PROX reaction is to reduce the CO content of hydrogen feed to proton exchange membrane fuel cells (PEMFC) by selective oxidation of CO in the presence of excess hydrogen. Both Pt and Pd on ceria are active in CO oxidation (without hydrogen) while Pd is poorly active in the presence of hydrogen. In this paper we aimed at finding the reasons of such behavior, using the same techniques for Pd/CeO 2 as for Pt/CeO 2 in Part I: catalytic tests, in-situ DRIFTS, high-pressure XPS, HRTEM and TDS. The reaction mechanism of CO oxidation (without hydrogen) was also examined. It does not occur via the exactly same mechanism on Pt and Pd/CeO 2 catalyst. In the presence of hydrogen (PROX) at low temperature (T=350-380 K), the formation of Pd β-hydride was confirmed by high-pressure in-situ XPS. Its formation greatly suppressed the possibility of CO oxidation, because oxygen both from gas phase and support sites reacted fast with hydride H to form water, and this water desorbed from Pd easily. Nevertheless, CO adsorption was not hampered here. These entities transformed mainly to surface formate and formyl (-CHO) species instead of oxidation as observed by DRIFTS. The participation of a low-temperature water-gas-shift type reaction proposed for the platinum system [Part I] was hindered. Increasing temperature led to decomposition of the hydride phase and a parallel increase in the selectivity towards CO oxidation was observed. However, it remained still lower on Pd/CeO 2 than on Pt/CeO 2 .

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Section: Introductionmentioning

confidence: 99%

Preferential CO oxidation in hydrogen (PROX) on ceria-supported catalysts, part II: Oxidation states and surface species on Pd/CeO2 under reaction conditions, suggested reaction mechanism

Pozdnyakova

Teschner

Wootsch

et al. 2006

Journal of Catalysis

205

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“…Most studies report advantageous effects of promoting Pt catalysts with Sn: Tin promotion improves catalytic activity, dehydrogenation selectivity, prevents Pt sintering, and decreases deactivation due to coke formation (see e.g. [4,[16][17][18][19][20][21][22][23] …”

Section: Introductionmentioning

confidence: 99%

In situ XPS investigation of Pt(Sn)/Mg(Al)O catalysts during ethane dehydrogenation experiments

et al. 2007

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Calcined hydrotalcite with or without added metal (Mg(Al)O, Pt/Mg(Al)O and Pt,Sn/Mg(Al)O) have been investigated with in situ X-ray Photoelectron Spectroscopy (XPS) during ethane dehydrogenation experiments. The temperature in the analysis chamber was 450ºC and the gas pressure was in the range 0.3 -1 mbar. Depth profiling of calcined hydrotalcite and platinum catalysts under reaction, oxidation and in hydrogenwater mixture was performed by varying the photon energy, covering an analysis depth of 10-21 Å. It was observed that the Mg/Al ratio in the Mg(Al)O crystallites does not vary significantly in the analysis depth range studied. This result indicates that Mg and Al are homogeneously distributed in the Mg(Al)O crystallites. Catalytic tests have shown that the initial activity of a Pt,Sn/Mg(Al)O catalyst increases during an activation period consisting of several cycles of reduction -dehydrogenation -oxidation. The Sn/Mg ratio in a Pt,Sn/Mg(Al)O catalyst was followed during several such cycles, and was found to increase during the activation period, probably due to a process where tin spreads over the carrier material and covers an increasing fraction of the Mg(Al)O surface. The results further indicate that spreading of tin occurs under reduction conditions. A PtSn 2 alloy was studied separately. The surface of the alloy was enriched in Sn during reduction and reaction conditions at 450°C. Binding energies were determined and indicated that Sn on the particle surface is predominantly in an oxidized state under reaction conditions, while Pt and a fraction of Sn is present as a reduced Pt-Sn alloy.

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“…Bimetallic PtSn catalysts are very efficient in different catalytic processes such as dehydrogenation or reforming [31,32]. PtSn or Pt 3 Sn catalysts are also used in oxidation or electrooxidation processes [33,35] and also in preferential oxidation of CO in the presence of H 2 [36,37]. Tin in the bimetallic PtSn catalyst is believed to promote oxygen adsorption on the platinum surface [38].…”

Section: Tof-sims Resultsmentioning

confidence: 99%

CO and H2 oxidation over Pt/BaSnO3 catalysts

Kocemba

Długołęcka

Wróbel-Jędrzejewska

et al. 2017

Reac Kinet Mech Cat

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This work reports the results of the studies on oxidation of carbon monoxide and H 2 over Pt supported on barium stannate (BaSnO 3 -perovskite type oxide). The composition and properties of Pt/BaSnO 3 catalysts were characterized by X-ray diffraction (XRD), time-of-flight secondary ion mass spectrometry (TOF-SIMS), H 2 and CO chemisorption, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) and tested in the reactions of carbon monoxide and hydrogen oxidation. It was stated that platinum strongly interacts with BaSnO 3 . The catalytic activity and adsorption properties of Pt/BaSnO 3 catalysts are determined by these interactions. The presence of different species (which generally can be labelled as [(Pt)BaSnO 3 ]) resulting from platinum and BaSnO 3 chemical interaction was found by the TOF-SIMS on surface of Pt/BaSnO 3 catalysts. The mechanism of CO and H 2 oxidation over Pt/BaSnO 3 catalysts was discussed in the light of strong interactions between Pt and BaSnO 3 .

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Bimetallic PtSn catalyst for selective CO oxidation in H2-rich gases at low temperatures

Cited by 164 publications

References 47 publications

Preferential CO oxidation in hydrogen (PROX) on ceria-supported catalysts, part II: Oxidation states and surface species on Pd/CeO2 under reaction conditions, suggested reaction mechanism

Preferential CO oxidation in hydrogen (PROX) on ceria-supported catalysts, part II: Oxidation states and surface species on Pd/CeO2 under reaction conditions, suggested reaction mechanism

In situ XPS investigation of Pt(Sn)/Mg(Al)O catalysts during ethane dehydrogenation experiments

CO and H2 oxidation over Pt/BaSnO3 catalysts

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