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Who should attend?
AutoChem users who utilize the TPR technique to characterize the interaction between the active species and the support in heterogeneous catalysis
Curriculum
- The use of the Autochem to perform TPR Profiles
- Calibration of the Thermal conductivity Detector
- Comprehension of different peaks in a TPR profile
- Effect of the support on the dispersion of the active species
- Effect of the ramping rate on the TPR profile
- Effect of the metal loading
- Quantification of the reducible species
Background
The activity of many solids, especially catalysts, strongly depends on certain specific parameters such as dispersion of the active phase (i.e. the active particle size), interaction between active species, and inert support, as well as interaction between different active species present in the same solid. These important parameters can be readily studied by the well-known technique of temperature-programmed reduction (TPR), in which a reducible gas, usually 10% H2 in either N2 or Ar, flows through the sample while temperature is increased at a constant rate. A thermal conductivity detector (TCD) placed downstream from the sample will detect and compute the change in hydrogen concentration while the oxide species present in the sample are reduced as a function of increasing temperature. The resulting TPR profile will contain one or more reduction peaks that illustrate how the reduction proceeds. It can be said that the number of peaks obtained corresponds to the number of transition phases that the oxide species passed through during reduction. The reduction temperature, on the other hand, will reveal the type of interaction that exists between active species and support. Moreover, a previously calibrated TCD will yield the total amount of hydrogen consumed during reduction, which in turn corresponds to the total reducible species in the catalyst.
Mark Stephens - email: mark.stephens@micromeritics.com phone: 770-662-3607
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