Towards the local structure of the Co(II), Ni(II), Cr(VI) and W(VI) ionic species formed upon impregnation on titania

Panagiotou, George D.; Petsi, Theano; Stavropoulos, John; Bourikas, Kyriakos; Garoufalis, Christos S.; Kordulis, Christos; Lycourghiotis, Alexis

doi:10.1016/s0167-2991(06)80984-5

Cited by 11 publications

(16 citation statements)

References 13 publications

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“…Therefore, the decrease of pH indicates the formation of inner sphere complexes by the nickel ions, en, and the surface of supports (Fig. 5) [46][47][48]. In our previous work [14,15], the activation time was found to be ∼12 min.…”

Section: The Processes Of New Nucleus Generation and Nickel Depositionmentioning

confidence: 99%

Synthesis of nickel nanoparticles supported on metal oxides using electroless plating: Controlling the dispersion and size of nickel nanoparticles

Zhang

et al. 2009

Journal of Colloid and Interface Science

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Section: The Processes Of New Nucleus Generation and Nickel Depositionmentioning

confidence: 99%

Synthesis of nickel nanoparticles supported on metal oxides using electroless plating: Controlling the dispersion and size of nickel nanoparticles

Zhang

et al. 2009

Journal of Colloid and Interface Science

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“…This ratio should be determined by the slope of a linear plot of the "amount of the H þ ions released (adsorbed)" Table 3 (193,194). A quite low value for this ratio (,1.0) suggests adsorption through electrostatic forces or hydrogen bonds.…”

Section: Interface Chemistry In Catalyst Preparationmentioning

confidence: 99%

The Role of the Liquid‐Solid Interface in the Preparation of Supported Catalysts

2006

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“…[16,17] The values of the aforementioned ratio determined at pH values of 6.5, 7.0, and 7.5 are, respectively, equal to 1.8, 1.9, and 2.0. These values are relatively large, which indicates…”

Section: à2mentioning

confidence: 99%

“…[16,17,39,[48][49][50] The slight increase of this ratio with increasing pH presumably reflects a slightly greater formation of the disubstituted inner-sphere complex at the expense of a monosubstituted inner-sphere complex. The exact local structure of the deposited [Ni-…”

Section: à2mentioning

confidence: 99%

“…[16] On the other hand, the impregnation of grains of a support with a solution containing transitionmetal ionic species (TMIS) of the active element to be deposited is critical for the preparation of a supported cataAbstract: The interfacial chemistry of the impregnation step involved in the preparation of nickel catalysts supported on titania is presented. Several methodologies based on deposition data, pH measurements, potentiometric mass titrations, and microelectrophoresis have been used in conjunction with diffuse reflectance UV/Vis/NIR spectroscopy, simulations, and semiempirical quantum chemical calculations.…”

Section: Introductionmentioning

confidence: 99%

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Interfacial Impregnation Chemistry in the Synthesis of Nickel Catalysts Supported on Titania

Bourikas

Stavropoulos

Garoufalis

et al. 2010

Chemistry A European J

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The interfacial chemistry of the impregnation step involved in the preparation of nickel catalysts supported on titania is presented. Several methodologies based on deposition data, pH measurements, potentiometric mass titrations, and microelectrophoresis have been used in conjunction with diffuse reflectance UV/Vis/NIR spectroscopy, simulations, and semiempirical quantum chemical calculations. Three mononuclear inner-sphere complexes were formed at the compact layer of the "titania/electrolyte solution" interface: A monosubstituted, dihydrolyzed complex above a terminal oxo group, a disubstituted, dihydrolyzed complex above two terminal adjacent oxo groups, and a disubstituted, nonhydrolyzed complex above one terminal and one bridging adjacent oxo groups. The monosubstituted, dihydrolyzed complex predominates. The contribution of the disubstituted configurations is also important at very low Ni(II) surface concentration, but it decreases as the Ni(II) surface concentration increases. In addition, bi- and trinuclear inner-sphere complexes were formed. The receptor site involves one bridging and two terminal oxo groups in the first case and two bridging and three terminal oxo groups in the second case. The relative surface concentrations of these configurations increase initially with Ni(II) surface concentration and then remain practically constant. The understanding of these interfacial processes at a molecular level is very important to shift the catalytic synthesis from an art to a science as well as to obtain strict control of the impregnation step and, to some extent, of the whole preparative sequence. This study is very relevant to the synthesis of submonolayer/monolayer nickel catalysts supported on TiO(2) following equilibrium deposition filtration (otherwise called equilibrium adsorption).

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Towards the local structure of the Co(II), Ni(II), Cr(VI) and W(VI) ionic species formed upon impregnation on titania

Cited by 11 publications

References 13 publications

Synthesis of nickel nanoparticles supported on metal oxides using electroless plating: Controlling the dispersion and size of nickel nanoparticles

Synthesis of nickel nanoparticles supported on metal oxides using electroless plating: Controlling the dispersion and size of nickel nanoparticles

The Role of the Liquid‐Solid Interface in the Preparation of Supported Catalysts

Interfacial Impregnation Chemistry in the Synthesis of Nickel Catalysts Supported on Titania

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