Structure of alumina surfaces

Цыганенко, А. А.; Mardilovich, Peter

doi:10.1039/ft9969204843

Cited by 243 publications

(226 citation statements)

References 27 publications

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“…This loss of water during the reaction is also seen as a negative band in the area around 3200 cm −1 . The loss of different types of free OH groups at the surface is evidenced as a small negative band at 3700 cm −1 (not shown in figure) (Tsyganenko and Mardilovich, 1996). When SO 2 is introduced simultaneously with NO 2 the bands of nitrate are still dominant, especially when the ratio of SO 2 to NO 2 is low, cf.…”

Section: Observed Productsmentioning

confidence: 99%

DRIFTS and Knudsen cell study of the heterogeneous reactivity of SO2 and NO2 on mineral dust

et al. 2003

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Abstract. The heterogeneous oxidation of SO 2 by NO 2 on mineral dust was studied using Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) and a Knudsen cell. This made it possible to characterise, kinetically, both the formation of sulfate and nitrate as surface products and the gas phase loss of the reactive species. The gas phase loss rate was determined to be first order in both SO 2 and NO 2 . From the DRIFTS experiment the uptake coefficient, γ , for the formation of sulfate was determined to be of the order of 10 −10 using the BET area as the reactive surface area. No significant formation of sulfate was seen in the absence of NO 2 . The Knudsen cell study gave uptake coefficients of the order of 10 −6 and 10 −7 for SO 2 and NO 2 respectively. There was no significant difference in uptake when SO 2 or NO 2 were introduced individually compared to experiments in which SO 2 and NO 2 were present at the same time.

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Section: Observed Productsmentioning

confidence: 99%

DRIFTS and Knudsen cell study of the heterogeneous reactivity of SO2 and NO2 on mineral dust

et al. 2003

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“…In this arrangement of atoms CN of any O atom is less than or equal to 4 in the bulk alumina, while on a surface it should be 3 or less. 24 Higher coordination number of Cl than oxygen at the surface is an indication of stronger adhesion of Cl on the surface. In a recent study 13 on Cl segregation in TiO 2 also, it was suggested that chlorine is strongly bonded at the TiO 2 surface, which makes it difficult to release it at lower temperatures and therefore it may get entrapped into closed porosity during the densification process.…”

Section: Coordination Numbersmentioning

confidence: 99%

Segregation of anion (Cl−) impurities at transparent polycrystalline α-alumina interfaces

Tewari

Nabiei

Cantoni

et al. 2014

Journal of the European Ceramic Society

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“…After the gold addition the carrier grains were smaller, which can be associated with the disintegration of the agglomerates presented in the beginning and secondly, the partial recrystallization of γ-Al2O3 which could have been possible for a sample calcined at a lower temperature (see Figure 5). In aqueous systems, γ-Al2O3 can again be transformed into aluminum hydroxide or aluminum oxyhydroxide, when the final heat treatment re-creates γ-Al2O3, but with a high specific surface area [35].…”

Section: Semmentioning

confidence: 99%

Effect of Support Structure in Au/Al₂O₃-TiO₂Catalysts in Low-Temperature CO Oxidation

2016

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Abstract. The aim of this study was to determine the effect of the support phase composition (Al 2 O 3 -TiO 2 ) and the addition of gold on the catalytic properties in low-temperature CO oxidation. In this paper, the physicochemical properties and results of catalytic measurements performed for the obtained samples were investigated. The catalyst carriers were prepared using the sol-gel method with alkoxide Al(C 3 H 7 O) 3 and Ti(C 3 H 7 O) 4 employed to obtain the corresponding oxides, in the case of which the molar ratio (Al 2 O 3 :TiO 2 ) was 0.75:0.25, 0.50:0.50 and 0.25:0.75, thus corresponding to the molar ratio of the Al:Ti elements, i.e. 1.5:0.25, 2:1 and 0.5:0.75 respectively. The gold catalysts were prepared through the deposition of gold by the deposition precipitation method using the theoretical loading of Au 2 wt.%. To examine the effect of the phase composition on the catalytic activity of the obtained samples, appropriate carriers were calcined at two different temperatures: 500°C and 1350°C. This made it possible to obtain the intended polymorphs of aluminum oxide and titanium dioxide (γ-Al 2 O 3 , α-Al 2 O 3 , anatase and rutile). For certain samples, calcined at a high temperature, the aluminum titanium oxide (Al 2 O 5 Ti) phase was also observed. The prepared samples were characterized by XRD, BET, SEM, and additionally both particle size distribution analysis and measurements of the catalytic activity were performed. The highest catalytic activity was shown by Au/75Al-25Ti_LT, where T 90 was about 110°C.

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Structure of alumina surfaces

Cited by 243 publications

References 27 publications

DRIFTS and Knudsen cell study of the heterogeneous reactivity of SO<sub>2</sub> and NO<sub>2</sub> on mineral dust

DRIFTS and Knudsen cell study of the heterogeneous reactivity of SO<sub>2</sub> and NO<sub>2</sub> on mineral dust

Segregation of anion (Cl−) impurities at transparent polycrystalline α-alumina interfaces

Effect of Support Structure in Au/Al₂O₃-TiO₂Catalysts in Low-Temperature CO Oxidation

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Structure of alumina surfaces

Cited by 243 publications

References 27 publications

DRIFTS and Knudsen cell study of the heterogeneous reactivity of SO&lt;sub&gt;2&lt;/sub&gt; and NO&lt;sub&gt;2&lt;/sub&gt; on mineral dust

DRIFTS and Knudsen cell study of the heterogeneous reactivity of SO&lt;sub&gt;2&lt;/sub&gt; and NO&lt;sub&gt;2&lt;/sub&gt; on mineral dust

Segregation of anion (Cl−) impurities at transparent polycrystalline α-alumina interfaces

Effect of Support Structure in Au/Al2O3-TiO2Catalysts in Low-Temperature CO Oxidation

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Product

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DRIFTS and Knudsen cell study of the heterogeneous reactivity of SO<sub>2</sub> and NO<sub>2</sub> on mineral dust

DRIFTS and Knudsen cell study of the heterogeneous reactivity of SO<sub>2</sub> and NO<sub>2</sub> on mineral dust

Effect of Support Structure in Au/Al₂O₃-TiO₂Catalysts in Low-Temperature CO Oxidation