Effect of the activation temperature on the state of gold supported on titania: An FT-IR spectroscopic study

Venkov, Tz.; Fajerwerg, Katia; Delannoy, Laurent; Klimev, Hr.; Hadjiivanov, Konstantin; Louis, Catherine

doi:10.1016/j.apcata.2005.11.019

Cited by 74 publications

(103 citation statements)

References 70 publications

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“…One of the explanations for the lack of such species is that Au 3+ ions are very easily reduced by CO [19,22,26,37,40]. Although reduction of Au 3+ may be kinetically insignificant at low temperatures, it has often been reported that no Au 3+ -CO species were even formed even at low temperatures [22, 37 -39].…”

Section: +mentioning

confidence: 99%

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Characterization of the Oxidation States of Supported Gold Species by IR Spectroscopy of Adsorbed CO

Mihaylov¹,

Knözinger²,

Hadjiivanov

et al. 2007

Chemie Ingenieur Technik

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147

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The use of IR spectroscopy of adsorbed CO for determination of gold speciation on supported gold catalysts is reviewed. Different ionic and metallic sites (Au 3+ , Au + , Au 0 , and Au -) can be differentiated on the basis of the frequency and stability of their surface carbonyl species formed after CO adsorption. In addition, the study of CO adsorption and reaction with other gases can provide unique information on the mechanisms of catalytic reactions with participation of CO. Finally, results from complementary techniques such as X-ray absorption spectroscopy, also useful for determination of gold oxidation state, are briefly considered.

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Section: +mentioning

confidence: 99%

“…Based on our work [22,37,38,65,64,69], as well as on analysis of the literature data [19,26,35,36 Figure 6. IR spectra of CO (equilibrium pressure of 1.1 kPa) adsorbed at room temperature on Au/NaY zeolite sample subjected to various pretreatments.…”

mentioning

confidence: 99%

Characterization of the Oxidation States of Supported Gold Species by IR Spectroscopy of Adsorbed CO

Mihaylov¹,

Knözinger²,

Hadjiivanov

et al. 2007

Chemie Ingenieur Technik

Self Cite

147

139

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“…The same band can be detected in the spectra of Au zeolites with different Au dispersions. Adsorption of CO to the Au species dispersed in the USY zeolite, which was hydrogen-reduced at 773 K, is manifested by the appearance of two bands at 2128 and 2092 cm ) can be attributed to metallic Au species, whereas the former to Au cationic species [21][22][23][24]. The origin of the 2128 cm band for CO 2 that resulted from the oxidation of CO by the Au oxide species.…”

Section: Ir Study Of Adsorbed Comentioning

confidence: 99%

Fabrication and Catalytic Activity of Thermally Stable Gold Nanoparticles on Ultrastable Y (USY) Zeolites

et al. 2013

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Au was deposited on ultrastable Y (USY) zeolites using an ion-exchange method. Up to 5.5 wt% Au was introduced into the NH 4 -form of USY zeolites. In contrast, deposition of Au hardly took place on the H-and Na-forms of Y-type zeolites, NH 4 -forms of mordenite, and ZSM-5. Treatment of the Au-loaded USY zeolite in a H 2 atmosphere, afforded Au 0 nanoparticles. These particles were thermally stable even at 973 K, where their mean particle diameter was 3.7 nm. In contrast, highly aggregated Au particles were observed after thermal treatment at temperatures lower than 523 K, followed by storage in air for a month. The resulting particle sizes were in good correlation with the IR band intensity of the adsorbed CO and the catalytic activity of Au in the aerobic oxidation of benzyl alcohol. The Au nanoparticles showed highest activity when the Au/USY zeolite was thermally treated at 673-973 K. A negligible deactivation was observed after repeating the reaction at least 12 times. In the case of Au/TiO 2 catalyst prepared by the deposition-precipitation method, the highest activity was observed at 573 K, which was lower than the temperature used for the Au/USY zeolites. This study demonstrated the potential use of the NH 4 -form of USY zeolites for supporting Au. OPEN ACCESSCatalysts 2013, 3 600

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“…10 shows that CO is adsorbed on metallic Au 0 sites (ν CO = 2086 cm -1 ), on positively polarized gold Au δ+ sites (ν CO = 2130 cm -1 ), 10,14 and on CUS Ti 4+ (ν CO = 2198 -2212 cm -1 ). 2,7,8,10,14 The presence of oxidized gold and unsaturated titanium suggests that lattice oxygen is extracted during the reaction with DMMP. Since analogous oxidation products (formate and CO) are not observed on the pure TiO 2 sample, it appears that gold promotes the extraction of lattice oxygen.…”

Section: Hrtem Of 22 Nm Particlesmentioning

confidence: 99%

“…The high reactivity of the Au-TiO 2 is likely due to a combination of factors, 6 including the presence of highly reactive surface oxygen. [7][8][9][10] In addition to providing information about the major surface-bound products, the infrared spectra enable us to monitor the oxidation state of the Au particles during the reaction. Previous theoretical 11 and experimental 12,13 studies have shown that the vibrational frequency of surface-bound CO is highly sensitive to the site of adsorption on Au surfaces.…”

Section: Hrtem Of 22 Nm Particlesmentioning

confidence: 99%

Adsorption and Decomposition of CWA Simulants on Single Crystal and Nanostructured Metal Oxides

Morris¹

2009

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Tech Final Report I. ForewordOur studies are directed at determining the adsorption mechanisms and reaction pathways for the chemical warfare agent simulant (CWA) for GB (Sarin) on metal oxide surfaces and nanoparticles. By learning about how surface structure, nanoparticle size, composition, and surface co-adsorbates affect the overall interfacial chemistry, we are providing insight that can be applied toward the development of effective sorbent materials for protection and decontamination. Our approach couples ultrahigh vacuum (UHV) surface analysis instrumentation with precision simulant dosing capabilities to explore agent reactivity on highly characterized and contaminant-free metal oxide surfaces. Our work during this funding period has focused on studying the uptake and decomposition of the simulant dimethyl methylphosphonate (DMMP) when it impinges on the surface of nanoparticulate systems.

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Effect of the activation temperature on the state of gold supported on titania: An FT-IR spectroscopic study

Cited by 74 publications

References 70 publications

Characterization of the Oxidation States of Supported Gold Species by IR Spectroscopy of Adsorbed CO

Characterization of the Oxidation States of Supported Gold Species by IR Spectroscopy of Adsorbed CO

Fabrication and Catalytic Activity of Thermally Stable Gold Nanoparticles on Ultrastable Y (USY) Zeolites

Adsorption and Decomposition of CWA Simulants on Single Crystal and Nanostructured Metal Oxides

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