Oxygen activation on oxide surfaces: A perspective at the atomic level

Freund, Hans‐Joachim

doi:10.1016/j.cattod.2014.05.037

Cited by 20 publications

(16 citation statements)

References 58 publications

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“…Finally, we may deal with the possible role of the defect structure of the oxidic supports. As mentioned in the introduction, in the explanation of the effectiveness of the TiO 2 as a support an increased attention is paid to the role of its oxygen vacancy [23][24][25]. As the carrier effect of TiO 2 (containing O vacancy) and that of ZnO (with excess Zn the interstitial position) is comparable, we may conclude that in this reaction the electronic property of the supporting oxides is more important than the nature of their defect structure.…”

Section: Discussionmentioning

confidence: 94%

“…After the first use of TiO 2 as a support [20,21] a dramatic increase in its application occurred [22]. Recently a greater attention is paid to the role of O vacancy in the catalytic and support effect of TiO 2 [23][24][25]. As the n-type character of TiO 2 is due to the O vacancy [26], it is not easy to differentiate between the role of O vacancy and the electric property.…”

Section: Introductionmentioning

confidence: 99%

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Reactions of ethane with CO2 over supported Au

Tóth¹,

Halasi²,

Solymosi³

2015

Journal of Catalysis

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Reaction of C 2 H 6 with CO 2 Au catalyst Effects of supports Electronic interaction between Au and oxides a b s t r a c tThe dehydrogenation of C 2 H 6 and its reaction with CO 2 have been investigated on Au deposited on various oxides. Both reactions occurred at relatively high temperatures, above 650 K. Ethylene formed in the dehydrogenation process with high selectivity, 94-98%, on most of the catalysts. The conversion of C 2 H 6 varied with the nature of support and fell in the range of 3-19%. Adding CO 2 to C 2 H 6 only slightly influenced the reaction of C 2 H 6 on Au/MgO and Au/Al 2 O 3 , but markedly increased the conversion of C 2 H 6 and changed its reaction pathways on Au deposited on n-type TiO 2 , CeO 2 and ZnO. Taking into account the properties of these oxides, we came to the conclusion that their electric behavior and not their defect structure play a dominant role in the enhanced activity of Au deposited on these supports. Based on the different work functions, an electronic interaction between Au particles and these oxides is proposed, which facilitates the formation of reactive negatively charged CO 2 .

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Section: Discussionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Reactions of ethane with CO2 over supported Au

Tóth¹,

Halasi²,

Solymosi³

2015

Journal of Catalysis

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“…This explanation was based on our early finding namely that variation of the work function of TiO 2 appreciably affected the catalytic performance of Ni evaporated on TiO 2 [11][12][13]. It appears that the interest in the carrier effect became more intensive nowadays thanks to the modern surface science methods, and the possible role of oxygen vacancy of TiO 2 came into prominence [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Catalytic and photocatalytic reactions of H2+CO2 on supported Au catalysts

Halasi¹,

Gazsi²,

Bánsági³

et al. 2015

Applied Catalysis A: General

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The interaction and the reaction between H 2 + CO 2 have been investigated on supported Au catalysts. By means of infrared spectroscopy, the formation of formate species was detected. The reaction between H 2 + CO 2 occurred above 475-500 K. The main reaction pathway was the formation of CO. The catalytic efficiency of Au sensitively depended upon the nature of the support. Highest conversion of CO 2 was found on Au particles dispersed on n-type oxides, TiO 2 , ZnO, and CeO 2. Au deposited on insulating oxides exhibited much less activity. At higher pressure, at 8.5 atm, a small amount of CH 4 and CH 3 OH were also produced. Illumination of the active catalysts induced the reaction even at room temperature resulting in the formation of CH 4. The high activity of Au particles supported by n-type semiconducting oxides was ascribed to the electronic interaction between Au and oxides leading to the activation of CO 2 .

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“…Even on uniform model systems [5,6], metal particles exhibit a broad size and shape distribution, being governed by structural irregularities of the oxide support. As a result, electronic characterization of unique deposits is impossible by spatially averaging spectroscopic techniques, and local approaches, such as electron [7,8] or scanning-tunneling microscopy (STM) need to be employed.…”

mentioning

confidence: 99%

Molecular Adsorption Changes the Quantum Structure of Oxide-Supported Gold Nanoparticles: Chemisorption versus Physisorption

et al. 2015

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STM conductance spectroscopy and mapping has been used to analyze the impact of molecular adsorption on the quantized electronic structure of individual metal nanoparticles. For this purpose, isophorone and CO2, as prototype molecules for physisorptive and chemisorptive binding, were dosed onto monolayer Au islands grown on MgO thin films. The molecules attach exclusively to the metal-oxide boundary, while the interior of the islands remains pristine. The Au quantum well states are perturbed due to the adsorption process and increase their mutual energy spacing in the CO2 case but move together in isophorone-covered islands. The shifts disclose the nature of the molecule-Au interaction, which relies on electron exchange for the CO2 ligands but on dispersive forces for the organic species. Our experiments reveal how molecular adsorption affects individual quantum systems, a topic of utmost relevance for heterogeneous catalysis.

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Oxygen activation on oxide surfaces: A perspective at the atomic level

Cited by 20 publications

References 58 publications

Reactions of ethane with CO2 over supported Au

Reactions of ethane with CO2 over supported Au

Catalytic and photocatalytic reactions of H2+CO2 on supported Au catalysts

Molecular Adsorption Changes the Quantum Structure of Oxide-Supported Gold Nanoparticles: Chemisorption versus Physisorption

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