Experimental procedures to evaluate dissolution, metal ion buffering, and catalytic precursor speciation during catalyst preparation

Mieth, J.A.; Huang, Y.-J.; Schwarz, John H.

doi:10.1016/0021-9797(88)90258-5

Cited by 19 publications

(5 citation statements)

References 7 publications

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“…According to most authors, a hydrated layer of hydroxide Al(OH) 3 forms at the surface of γ -Al 2 O 3 after the oxide is suspended in an aqueous solution, without dissolution of the support [17,18]. Actually, Eng et al [19] have shown with the help of a surface diffraction technique (crystal truncation rod diffraction) that the (0001) single-crystal surface of α-Al 2 O 3 in ambient air is intermediate between the bulk structure of α-Al 2 O 3 and gibbsite Al(OH) 3 .…”

Section: Introductionmentioning

confidence: 99%

Transformations of γ-alumina in aqueous suspensions

Carrier¹,

Marceau²,

Lambert³

et al. 2007

Journal of Colloid and Interface Science

136

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Section: Introductionmentioning

confidence: 99%

Transformations of γ-alumina in aqueous suspensions

Carrier¹,

Marceau²,

Lambert³

et al. 2007

Journal of Colloid and Interface Science

136

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“…The contact of alumina with acidic solutions and subsequent dissolution effects have been reported in the literature [44][45][46]. The presence of chelating compound (e.g., EDTA) have an influence on the partial removal of metal ions from the support framework [47].…”

Section: Resultsmentioning

confidence: 99%

Ruthenium red interaction with alumina surface—FT-IR/PAS studies

Ryczkowski

2004

Vibrational Spectroscopy

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“…40 The deposition of CeO 2 on silicon occurs through the formation of a gel consisting of Ce͑OH͒ 2 2+ ionic species which are reduced in the presence of OH − ions at the interface solution/substrate. In our present case, a hydrated layer of Al͑OH͒ 3 forms at the surface of ␥Ј-Al 2 O 3 when the oxide is suspended in aqueous solutions, 41 which in contact with the CeCl 3 aqueous solution should also form a gel. The formation of CeAlO 3 nanowires inside the pores of the template of amorphous Al 2 O 3 probably involves the consumption of part of the ␥Ј-phase by reaction with Ce 3+ ions present in the solution inside the pores.…”

Section: K102mentioning

confidence: 97%

CeAlO[sub 3] Nanowire Arrays in Porous Anodic Alumina Templates

Müller

Fernandes

Lipinski

et al. 2010

Electrochem. Solid-State Lett.

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We investigated the fabrication of highly ordered CeAlO 3 nanowire arrays in porous anodic alumina ͑PAA͒ templates by electrodeposition. The electrochemical synthesis was performed under potentiostatic conditions using an aqueous bath of cerium chloride as the electrolyte. PAA templates were obtained in a two-step process involving aluminum anodization and chemical etching to open the pores and remove the barrier layer formed inside the pores. Scanning electron microscopy and transmission electron microscopy as well as X-ray photoelectron spectroscopy analyses were performed to demonstrate the feasibility to obtain stoichiometric CeAlO 3 stabilized in highly ordered nanowire arrays in Al 2 O 3 template.The synthesis of surfaces covered by a dense array of nanometerscaled structures has stimulated intensive research activities because of their interest in the understanding of basic concepts and potential technological applications, such as catalysis, optoelectronics, information storage, and sensing.Ordered nanostructures with different sizes can be synthesized using different kinds of templates, such as organic macromolecules, 1 nanometer-sized granulars of silica, 2 polycarbonate membranes, and porous anodic alumina ͑PAA͒. 3-5 Among these templates, the PAA templates have received considerable attention due to their unique structure properties, such as high density ͑ Ͼ 10 10 cm −2 ͒ of parallel pores with controllable diameter ͑from 4 to 100 nm͒, extremely narrow size distribution for pore diameters and their intervals over large areas ͑ Ͼ 1 cm 2 ͒, and ideally cylindrical shape of pores 6-8 within typical membrane thicknesses ranging from 10 to 100 m. 3,9,10 Here we investigate the formation of cerium aluminate ͑CeAlO 3 ͒ nanowires in PAA templates. CeAlO 3 is an orthoaluminate of the LnAlO 3 type ͑Ln = lanthanides͒, which belongs to the distorted perovskite structures. At room temperature, the structure of CeAlO 3 differs from an ideal cubic perovskite and a tetragonal symmetry ͑a = 3.7669 Å, c = 3.7967 Å, SG P4/mmm͒ 11 was proposed, in which the Ce atoms between the AlO 6 octahedra are tilted around the pseudocubic c-axis with the tilting angle of about 6.3°. More recently, the Rietveld analysis of CeAlO 3 revealed a super cell ͑a = 5.324 89 Å, c = 7.589 76 Å͒, with the space group I4/mcm. 12,13 Shelykh et al. 14 reported a surprisingly high dielectric constant, r , of 3000-10 000 measured at a frequency of 1 kHz. Wang et al. 15 reported that CeAlO 3 exhibits r Ͼ 600 in the frequency range of 10 kHz-10 MHz, which is of importance for ferroelectrical applications ͑e.g., resonators and antennas͒. 16 In general, intrinsic r values in excess of ϳ100 require some form of dipolar polarization mechanism in addition to the electronic and ionic polarizabilities. The origin of such high r is still controversial since the tetragonal centrosymmetric space group I4/mcm of CeAlO 3 precludes the occurrence of ferroelectricity as a possible origin for the apparently large r . An alternative explanation of the unexpectedly ...

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Experimental procedures to evaluate dissolution, metal ion buffering, and catalytic precursor speciation during catalyst preparation

Cited by 19 publications

References 7 publications

Transformations of γ-alumina in aqueous suspensions

Transformations of γ-alumina in aqueous suspensions

Ruthenium red interaction with alumina surface—FT-IR/PAS studies

CeAlO[sub 3] Nanowire Arrays in Porous Anodic Alumina Templates

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