Catalytically active gold sites: nanoparticles, borderline sites, clusters, cations, anions? FTIR spectra analysis of12CO and of12CO-13CO isotopic mixtures

Vindigni, Floriana; Manzoli, Maela; Chiorino, A.; Boccuzzi, F.

doi:10.1007/bf03214920

Cited by 39 publications

(44 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The band at 2116 cm -1 is due to the adsorption of CO to metallic gold [56]. Boccuzzi et al [57][58][59] have proposed that CO stretching band on gold nanoparticles in the range of 2106-2118 cm -1 relates to CO adsorption to corner sites. The band at 2207 cm -1 is likely due to CO adsorbed to Au 3?…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Gold Stabilized by Nanostructured Ceria Supports: Nature of the Active Sites and Catalytic Performance

et al. 2011

View full text Add to dashboard Cite

The interaction of gold atoms with CeO 2 nanocrystals having rod and cube shapes has been examined by cyanide leaching, TEM, TPR, CO IR and X-ray absorption spectroscopy. After deposition-precipitation and calcination of gold, these surfaces contain gold nanoparticles in the range 2-6 nm. For the ceria nanorods, a substantial amount of gold is present as cations that replace Ce ions in the surface as follows from their first and second coordination shells of oxygen and cerium by EXAFS analysis. These cations are stable against cyanide leaching in contrast to gold nanoparticles. Upon reduction the isolated Au atoms form finely dispersed metal clusters with a high activity in CO oxidation, the WGS reaction and 1,3-butadiene hydrogenation. By analogy with the very low activity of reduced gold nanoparticles on ceria nanocubes exposing the {100} surface plane, it is inferred that the gold nanoparticles on the ceria nanorod surface also have a low activity in such reactions. Although the finely dispersed Au clusters are thermally stable up to quite high temperature in line with earlier findings (Y. Guan and E. J. M. Hensen, Phys Chem Chem Phys 11:9578, 2009), the presence of gold nanoparticles results in their more facile agglomeration, especially in the presence of water (e.g., WGS conditions). For liquid phase alcohol oxidation, metallic gold nanoparticles are the active sites. In the absence of a base, the O-H bond cleavage appears to be rate limiting, while this shifts to C-H bond activation after addition of NaOH. In the latter case, the gold nanoparticles on the surface of ceria nanocubes are much more active than those on the surface of nanorod ceria.

show abstract

Section: Resultsmentioning

confidence: 99%

“…New bands appear at 2028, 2084, and 2103 cm -1 . The former two bands are assigned to CO adsorption on anionic gold clusters [56,58,59]. The latter band at 2103 cm -1 has been assigned to CO adsorption on well-reduced gold particles.…”

Section: Resultsmentioning

confidence: 99%

Gold Stabilized by Nanostructured Ceria Supports: Nature of the Active Sites and Catalytic Performance

et al. 2011

View full text Add to dashboard Cite

show abstract

“…The surface negative charge decreases with the size of the Au clusters. Anionic Au atoms in the cluster have a stronger interaction with O 2 than a neutral Au atom [20,63,[86][87][88][89][90][91][92][93][94][95]. These findings suggest that the active sites for oxygenation on the supported and unsupported Au catalysts [63,93,96] are Au atoms which are negatively charged.…”

Section: Introductionmentioning

confidence: 88%

“…Metal/metal interfaces show novel physical and chemical properties [4,9,[14][15][16]. In particular, bimetallic surfaces involving gold [7,[17][18][19] are extensively investigated due to the high catalytic activity of nanostructured gold systems [20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

O2 dissociation in Na-modified gold ultrathin layer on Cu(111)

Politanoa

Chiarello

2010

Gold Bull

View full text Add to dashboard Cite

High-resolution electron energy loss spectroscopy has been used to investigate the catalytic properties of Na-doped Au monolayer grown on Cu(111). The presence of Na atoms allows the dissociation of oxygen molecules and the stabilization of atomic oxygen. The strong reduction of the dissociation barrier for O 2 promoted by Na could readily favor many surface chemical reactions, due to the key role of atomic oxygen in many oxidation processes catalyzed by gold.

show abstract

Fully Reversible Metal Deactivation Effects in Gold/Ceria–Zirconia Catalysts: Role of the Redox State of the Support

et al. 2010

View full text Add to dashboard Cite

Strong and reversible modification of the chemical properties of supported Au nanoparticles caused by alternating oxidizing (a and c) and reducing (b) pretreatment of Au/CeO2–ZrO2 catalysts were revealed by a methodology that combines FTIR spectroscopy (see picture), studies on the volumetric adsorption of CO and ultimate oxygen storage capacity, determination of metal dispersion by electron microscopy, and X‐ray photoelectron spectroscopy.

show abstract

Catalytically active gold sites: nanoparticles, borderline sites, clusters, cations, anions? FTIR spectra analysis of12CO and of12CO-13CO isotopic mixtures

Cited by 39 publications

References 24 publications

Gold Stabilized by Nanostructured Ceria Supports: Nature of the Active Sites and Catalytic Performance

Gold Stabilized by Nanostructured Ceria Supports: Nature of the Active Sites and Catalytic Performance

O2 dissociation in Na-modified gold ultrathin layer on Cu(111)

Fully Reversible Metal Deactivation Effects in Gold/Ceria–Zirconia Catalysts: Role of the Redox State of the Support

Contact Info

Product

Resources

About