The temperature dependence of the point of zero charge of $gamma;-Al2O3, TiO2, and physical mixtures

Subramanian, S.; Schwarz, John H.; Hejase, Z.

doi:10.1016/0021-9517(89)90360-6

Cited by 31 publications

(14 citation statements)

References 11 publications

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“…The PZC of the particles, determined by titration of suspensions at different ionic strengths at 25 uC or 60 uC, is located near pH 5.3, in accordance with reported data. 32,33 The experimental variation of the particle surface electrostatic charge density, s, with pH is shown in Fig. 5b.…”

Section: Surface Charge Density Of Anatase Particlesmentioning

confidence: 99%

Size tailoring of TiO2 anatase nanoparticles in aqueous medium and synthesis of nanocomposites. Characterization by Raman spectroscopy

et al. 2003

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Nanoparticles of anatase with mean size in the range 5-10 nm were prepared by precipitation of TiCl 4 in aqueous medium in the range 2 ¡ pH ¡ 6. Hydroxylation of TiCl 4 at room temperature leads instantaneously to an amorphous titanium oxyhydroxide phase which crystallizes as anatase upon aging at 60 uC in suspension. Small amounts of brookite or rutile are concurrently obtained depending on the acidity. The size of anatase particles was characterized by X-ray diffraction, electron microscopy and Raman spectroscopy. The latter was also used to determine the particle size and to characterize the crystallinity of particles through the phonon confinement effect. The particle size, dependent on the acidity, is closely related to the electrostatic surface charge density of particles. The size variation was interpreted as resulting from a lowering of the interfacial tension due to the protonation of particle surface groups. Composite materials were synthesized by polymerisation of silica in aqueous sols of anatase. The dispersed anatase nanoparticles are stable against the transformation to rutile up to 1000 uC.

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Section: Surface Charge Density Of Anatase Particlesmentioning

confidence: 99%

Size tailoring of TiO2 anatase nanoparticles in aqueous medium and synthesis of nanocomposites. Characterization by Raman spectroscopy

et al. 2003

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“…It was Berube and de Bruyn who studied the effect of temperature on PZC. Studies of that kind were next conducted by Tewari et al, , Fokkink et al, , Schwarz and co-workers, Kuo and Yen, Akratopulu et al, , Blesa et al, and Kosmulski et al , The influence of temperature on the surface charge vs pH profiles was studied by Blesa and co-workers, , Brady, and Kosmulski . Valuable information concerning that problem has been collected in the review by Machesky et al…”

Section: Introductionmentioning

confidence: 99%

Calorimetric Effects Accompanying Ion Adsorption at the Charged Metal Oxide/Electrolyte Interfaces: Effects of Oxide Surface Energetic Heterogeneity

Rudziński¹,

Charmas²,

Piasecki³

et al. 1998

Langmuir

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A quantitative theoretical analysis of the enthaplic effects accompanying ion adsorption at the oxide/electrolyte interface, based on a model of energetically heterogeneous surface oxygens, is presented. The triple layer complexation model is accepted, along with the 2-pK charging mechanism. For the purpose of illustration a set of experimental data is subjected to that quantitative analysis including titration curves, radiometrically measured individual iostherms of ions, and calorimetric titration data for the alumina/NaCl electrolyte system. Two models of energetic heterogeneity were taken into consideration. One of them assumes that the binding-to-oxygen energies of the surface complexes vary but are highly correlated when going from one to another surface oxygen. The other model of surface heterogeneity assumes that these correlations are very small. Our numerical simultaneous analysis of the titration data, of the individual isotherms of Na+ and Cl- adsorption, and of the accompanying heat effects advocates strongly for the model of surface heterogeneity assuming small correlations to exist. A good simultaneous fit of all three kinds of experimental data is obtained, with a small uncertainty as for the values of the estimated adsorption parameters. A simultaneous fit of the measured enthalpic effects appears to be an especially strong criterion for a proper choice of adsorption parameters.

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“…The point of zero charge of the supports was measured by the simplified mass titration method [13,14]. The slurry used for the measurement contained 0.4 g of support and 4 mL of water.…”

Section: Characterization and Activitymentioning

confidence: 99%

Support effect in the hydrodesulfurization of thiophene over rhodium sulfide

Kaluža

Vı́t

Zdražil

2010

Reac Kinet Mech Cat

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The effect of support on thiophene hydrodesulfurization activity over rhodium sulfide was studied. The loading was 5 wt% and the supports were (surface areas S BET in m 2 g -1 in parenthesis): C (1100), Nb 2 O 5 (99), ZrO 2 (108), TiO 2 (140), SiO 2 (289), MgO (300) and 11 Al 2 O 3 (77-279). The activity at 400°C decreased in the order (relative activity in parenthesis): C (4.44), Al 2 O 3 (0.98-0.32), Nb 2 O 5 (0.54), ZrO 2 (0.50), TiO 2 (0.48), SiO 2 (0.26), MgO (0.19), commercial CoMo/Al 2 O 3 (1.00). The activity did not correlate with S BET , point of zero charge PZC of the support and the ratio S/Rh in the presulfided catalysts. The broad range of activities of Rh/Al 2 O 3 illustrate that secondary factors such as S BET , texture, PZC, impurities and additives might be as important as the principal type of the support.

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The temperature dependence of the point of zero charge of $gamma;-Al2O3, TiO2, and physical mixtures

Cited by 31 publications

References 11 publications

Size tailoring of TiO2 anatase nanoparticles in aqueous medium and synthesis of nanocomposites. Characterization by Raman spectroscopy

Size tailoring of TiO2 anatase nanoparticles in aqueous medium and synthesis of nanocomposites. Characterization by Raman spectroscopy

Calorimetric Effects Accompanying Ion Adsorption at the Charged Metal Oxide/Electrolyte Interfaces: Effects of Oxide Surface Energetic Heterogeneity

Support effect in the hydrodesulfurization of thiophene over rhodium sulfide

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