Nanostructural Evolution of a Pt/CeO2Catalyst Reduced at Increasing Temperatures (473–1223 K): A HREM Study

Bernal, S.; Calvino, José J.; Gatica, José M.; Larese, C.; López-Cartés, C.; Pérez-Omil, Jose A.

doi:10.1006/jcat.1997.1707

Cited by 77 publications

(56 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In Pt/CeO 2 and Pt/CeTbO x catalysts, similar decoration effects have been detected 16,17,38 after reduction in hydrogen at 973 K. Figure 7(d) shows precisely such an HREM image recorded on a 5% Pt/Ce 0.8 Tb 0.2 O 2 catalyst after reduction in pure hydrogen at 973 K for 1 h. Note that in this case the Pt particle is also surrounded at the bottom by a shell of support. On the uppermost (111) plane of this particle a row of black dots, with a separation of ¾0.34 nm from each other, partially covering the surface, is also evident.…”

Section: Surface and Interface Detailssupporting

confidence: 56%

Structure of highly dispersed metals and oxides: exploring the capabilities of high-resolution electron microscopy

Bernal

Baker

Burrows

et al. 2000

Surf. Interface Anal.

Self Cite

View full text Add to dashboard Cite

The potential applicability of high-resolution electron microscopy (HREM), in combination with image analysis and image simulation tools, to retrieve structural information from nanometre-sized particles present in oxide-supported metal and oxide catalysts is analysed. Specifically, the possibilities and limitations of this technique to determine features such as the size, morphology and chemical nature of the particles, their surface structure and their structural relationship with the support are considered through the discussion of several examples.The interpretation of a series of HREM images of Pt and Rh catalysts supported on cerium oxides after treatments under different redox environments illustrates the case of highly dispersed metals. In addition, the results obtained in this study provide an approximate picture of the evolution of metal-support interaction effects in this family of catalysts, which is closely related to three-way catalysts (TWCs). The results of a nanostructural investigation of two catalyst systems, one consisting of MgO-supported neodymia clusters and the second of vanadium-magnesium oxide also supported on MgO, provide the examples for supported oxide catalysts. These find application in oxidation reactions. For the former, the growth of neodymia in the form of rounded patches in a parallel orientation relationship with the support has been observed. For the vanadiacontaining catalysts, the formation of a weakly ordered MgV 2 O 4 spinel surface phase on the MgO support crystallites, after exposure to typical reaction conditions in the oxidative dehydrogenation of propane, has been confirmed. The structural relationship at the spinel/MgO interface has also been established. Copyright

show abstract

Section: Surface and Interface Detailssupporting

confidence: 56%

Structure of highly dispersed metals and oxides: exploring the capabilities of high-resolution electron microscopy

Bernal

Baker

Burrows

et al. 2000

Surf. Interface Anal.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Electron microscopy studies have shown that after high temperature reduction, partially reduced oxide species migrate, and decorate the metal surface [4][5][6]11,12]. Bernal, et al have shown that in the case of a Pt/CeO 2 catalyst this decoration occurs at a reduction temperature of 973 K and CePt 5 particles are formed at temperatures of 1173 K [13]. This decoration effect occurs at lower temperatures for Metal/TiO 2 systems, and Datye, et al have postulated that the SMSI effect is different for Metal/TiO 2 and Metal/CeO 2 systems [7].…”

Section: Introductionmentioning

confidence: 99%

Effect of Sn addition to Pt/CeO2–Al2O3 and Pt/Al2O3 catalysts: An XPS, 119Sn Mössbauer and microcalorimetry study

Serrano‐Ruiz

Huber

Sánchez-Castillo

et al. 2006

Journal of Catalysis

144

View full text Add to dashboard Cite

The effect of Sn addition to Pt/CeO 2 -Al 2 O 3 and Pt/Al 2 O 3 catalysts was studied with X-ray photoelectron spectroscopy (XPS), 119 Sn Mössbauer spectroscopy and adsorption microcalorimetry of CO at room temperature. Catalysts were reduced in situ at 473 ("non-SMSI state") and 773 K ("SMSI state"). 119 Sn Mössbauer and XPS results indicated that the presence of cerium in bimetallic catalysts inhibited reduction of tin.Furthermore, it was found that tin facilitated reduction of cerium (IV) to cerium (III).Microcalorimetric analysis indicated that cerium addition caused the appearance of a more heterogeneous distribution of active sites, whereas tin addition led to a higher homogeneity of these sites.

show abstract

“…CO hydrogenation on Pt and Rh is known to be promoted by addition of ceria to an inert support [11,41] which also favours formation of longer chain hydrocarbons and/or alcohols [17]. Compared to MCB hydrogenolysis, it proceeds at a somewhat lower rate and higher reaction temperatures had to be chosen (523 K on Pt and 473 K on Rh).…”

Section: Hydrogenation Of Comentioning

confidence: 99%

“…So far, ex situ electron microscopy studies have revealed metal particle decoration after hydrogen treatment at 973 K and above [10][11][12][13]. Nevertheless, chemisorption data and catalytic measurements indicate appreciable interaction between ceria and noble metals already after www.elsevier.com/locate/apcata Applied Catalysis A: General 294 (2005) 279-289 reduction at 773 K and below [12,[14][15][16].…”

Section: Introductionmentioning

confidence: 98%

Interaction of Pt and Rh nanoparticles with ceria supports: Ring opening of methylcyclobutane and CO hydrogenation after reduction at 373–723K

Fuchs

Jenewein

Penner

et al. 2005

Applied Catalysis A: General

Self Cite

View full text Add to dashboard Cite

Nanostructural Evolution of a Pt/CeO2Catalyst Reduced at Increasing Temperatures (473–1223 K): A HREM Study

Cited by 77 publications

References 22 publications

Structure of highly dispersed metals and oxides: exploring the capabilities of high-resolution electron microscopy

Structure of highly dispersed metals and oxides: exploring the capabilities of high-resolution electron microscopy

Effect of Sn addition to Pt/CeO2–Al2O3 and Pt/Al2O3 catalysts: An XPS, 119Sn Mössbauer and microcalorimetry study

Interaction of Pt and Rh nanoparticles with ceria supports: Ring opening of methylcyclobutane and CO hydrogenation after reduction at 373–723K

Contact Info

Product

Resources

About