Introduction isothermal microcalorimeter

The adsorption up to 50 bars was carried out by means of a Tian-Calvet type isothermal microcalorimeter built in the former CNRS Centre for Thermodynamics and Microcalorimetry. For these experiments, around 2 g of sample was used which were outgassed by Controlled Rate Thermal Analysis (CRTA) [7]. The experiments were carried out at 30°C (303 K). Approximately 6 hours is required after introduction of the sample cell into the thermopile for the system to be within 1/100 of a degree Celsius. At this point the baseline recording is taken for 20 minutes. After this thermal equilibrium was attained, a point by point adsorptive dosing procedure was used. Equilibrium was considered attained when the thermal flow measured on adsorption by the calorimeter returned to the base line. For each point the thermal flow and the equilibrium pressure (by means of a 0-70 bar MKS pressure transdueer providing a sensitivity of 0.5% of the measured value) were recorded. The area under the peak in the thermal flow, Q eas, is measured to determine the pseudo-differential... 

It is worth recalling that the entropy of adsorption may be obtained from calorimetric experiments only if the heat exchange is reversible. A formula for evaluating the standard adsorption entropy Aa5 °from a reversible adsorption volumetric-calorimetric data was proposed by Garrone et al. [91] and applied to a selection of quasi-ideal systems, [97] consisting of CO adsorbed on non d/d metal oxides, at the surface of which cus cations acting as Lewis acidic sites were exposed. An isothermal microcalorimeter with a discontinuous (stepwise) introduction of the adsorptive, as the one described here, was fruitfully employed. 

In the reported examples, an isothermal microcalorimeter with a discontinuous (stepwise) introduction of the adsorptive was fmitfully employed. An alternative, suitable way to collect the experimental data required for determining the enthalpy and entropy changes accompanying the adsorption process is to follow the procedure implying the slow-and-constant adsorptive introduction which was extensively described in Ref. [99]. 

The results of CO adsorption microcalorimetry described in this overview were collected with a differential and isothermal microcalorimeter (Tian-Calvet Microcalorimeter) linked to a static volumetric system. The equipment permits the introduction of successive small doses of CO onto the catalyst. Both the calorimetric and the volumetric data were stored and analyzed by microcomputer processing. The obtained data are presented as differential heats versus the amount of CO adsorbed... 

Isothermal titration calorimetry (ITC) has long been recognized as a useful tool for the evaluation of binding constants [51]. The field of calorimetry changed markedly during the early 1990s with the introduction of commercial titration microcalorimeters [52]. These devices, available from several suppliers, operate with volumes near one to two milliliters. Virtually all the data reported to date on the thermody-... 

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