Stoeckli, Fritz

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Accès libre
On the correlation between micropore distribution obtained from molecular probes and from high resolution electron microscopy
(1989)
Stoeckli, Fritz
;
Innes, R. W.
;
Fryer, J. R.
By using immersion calorimetry with liquids of various molecular dimensions, the distributions of the micropore sizes have been obtained for a number of active carbons, for the range 0.3 to 0.75 nm. These carbons have also been examined by high-resolution electron microscopy, the results from both techniques being displayed in the form of histograms. The agreement between the two methods appears to be good and provides possible evidence of the reduced interaction radius of adsorbed molecules and of exfoliation.
Accès libre
The Microporosity of Activated Carbon Fibre KF1500 Assessed by Combined CO₂ Adsorption and Calorimetry Techniques and by Immersion Calorimetry
(2000)
Guillot, André
;
Stoeckli, Fritz
;
Bauguil Y.
The microporous structure of the activated carbon fibre KF1500 was investigated by applying a new technique as presented here. This was based on a combination of high-pressure CO₂ adsorption measurements between 253 K and 353 K with direct measurement of the differential heats of adsorption at 298 K at low and medium coverages. The validity of this approach was tested by using two activated carbons which has been characterized previously by a variety of techniques, including immersion calorimetry. It appears that a combination of high-pressure adsorption and calorimetry with CO₂ alone is a useful tool for the characterization of the whole range of microporosity. This approach confirms earlier observations, according to which the initial stage of adsorption by strongly activated carbons corresponds to adsorption on the walls of large micropores rather than to the primary filling of small micropores.
Accès libre
On the Physical Meaning of Parameters E_o and b in Dubinin's Theory
(1980)
Morel, Daniel
;
Stoeckli, Fritz
A comparative study of limiting adsorption energies in microporous carbons and on graphitized carbon blacks shows that their difference is proportional to the quantity β E_o, which appears in Dubinin's theory. It follows that the characteristic energy E_o must be related to an average pore size, as found empirically. The affinity coefficient β, on the other hand, can be regarded as a shifting factor, directly related to the ratio of gas-solid adsorption potentials.
Accès libre
Thermodynamics of Mixtures. Excess Volumes and Energies of Mixing of Cycloalkane Mixtures (Cyclopentane to Cyclooctane)
(1973)
Duc, Luong Minh
;
Abdellah, Z.
;
Stoeckli, Fritz
The volumes of mixing for the systems cyclopentane + cyclohexane, cyclopentane + cycloheptane, cyclohexane + cycloheptane (at 20°C), and cyclopentane + cyclooctane, cyclohexane + cyclooctane, cycloheptane + cyclooctane (at 30 °C) have been measured with a dilatometer. All systems show volume contractions, except the first. The energies of mixing are also given. They vary from 7 to 55 J/mol for equimolar solutions.
Accès libre
The external surface of microporous carbons, derived from adsorption and immersion studies
(1984)
Stoeckli, Fritz
;
Kraehenbuehl, F.
Three typical samples of active carbons have been investigated by using immersion calorimetry and adsorption techniques (t-plot, t/F method of Dubinin and direct analysis of the adsorption isotherm before and after prefilling), in order to obtain their external surface area. The different techniques lead to consistent results.
Accès libre
The role of textural characteristics and oxygen-containing surface groups in the supercapacitor performances of activated carbons
(2006)
Centeno, Teresa A.
;
Stoeckli, Fritz
It is suggested that the specific capacitance C₀ of activated carbons at low current densities (d ~ 1 mA cm⁻²) consists, to a good first approximation, of two contributions. For the H₂SO₄ electrolyte they correspond to approximately 0.080 F m−2 from the total accessible surface area and an additional pseudo-capacitance of 63 F mmol⁻¹ from the surface species generating CO in thermally programmed desorption (TPD). The new correlation proposed here is an alternative to Shi's earlier approach which considered contributions from the microporous and the external surface areas. Furthermore, it appears that the variation of the specific capacitance C at high current densities d (up to 100–150 mA cm⁻²) depends essentially on the CO₂-generating surface groups and on 1/L₀, the inverse of the average micropore width.
Accès libre
On the description of micropore distributions by various mathematical models
(1989)
Stoeckli, Fritz
Accès libre
Low Temperature Thermodynamics. The excess Gibbs function and the volumes of mixing for the system methane +
(1969)
Stoeckli, Fritz
;
Staveley, L. A. K.
The excess Gibbs function G^e and the excess volumes of mixing I/^e have been measured at the methane triple point (90.68 K) for the system methane+propane. They were compared with McGlashan's recent theory for mixtures of molecules of different sizes.
Accès libre
Adsorption of Methane by microporous Carbons at high Pressures and Temperatures
(1998)
Pribylov, A. A.
;
Stoeckli, Fritz
Accès libre
Binary Adsorption of Vapours in Active Carbons Described by the Dubinin Equation
(1996)
Lavanchy, André
;
Stöckli, M.
;
Wirz, C.
;
Stoeckli, Fritz

Stoeckli, Fritz

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