Collaborative Research Centre 546
"Structure, Dynamics and Reactivity of Aggregates of Transition Metal Oxides"
Project B7
General information
| Thema: |
Technical V2O5/TiO2-model
catalysts: Preparation, and investigation of interaction between active
component and support
|
Leader:
|
Prof. Dr. Helmut Schubert
Technische Universität Berlin
Insstitut für Werkstoffwissenschaften und -technologien
Englische Straße 20
10587 Berlin
Telefon: 030 314 23425
Telefax: 030 2093-6966
E-Mail-Adresse: schubert@ms.tu-berlin.de
|
Abstract:
This project plans to set-up experiments
which bridge the gap between atomistic aspects and real catalysts, based on
model systems and micro scale investigations.
The profound knowledge on atomistic processes as derived in this SFB is the
basis for further investigations on larger scale. Thus, experimental model have
to be set-up which reflect to properties of real catalysts but which also enable
detailed physical investigations. Significant differences are the defect.
Situation, the state of hydrolysis and the morphology of the catalyst. A good
technical model system has to pay attention to these influences. Hence, they
have to give access to high resolution physical investigations which requires
plane surfaces. The experience of the TU Berlin preparing technical catalysts
is used for preparing well defined technical model systems. A major influence
is the difference in thermal expansion which results in interface stresses.
They depend on the type of support and the size of the interface between the
support and the active compound. Model specimens will be prepared which are
subject to XRD and HR-TEM (B2) investigations. HT- XRD investigations on pure
phases are used to derive lattice parameters and thermal strains which both
can be used to determine stresses if elastic parameters are known (C4). The
appropriate method for stress analysis in small particles is the Warren Averbach
method which will be associated by stress modelling. The morphology of the interfaces
are inspected by SEM and TEM (B2). Hence, strong changes are induced by changing
the partial pressure (feed gas). Using defined atmospheres (B4) leads to specimens
with a different state of valance (B2) and which are strained. Again, strains
are derived from XRD data.
In order to understand the long time behaviour of catalyst investigations on
the phase relations are planned. Again specimens are treated under various conditions
and inspected by a set of methods. All material changes are correlated to changes
in catalytic behaviour (B6 and B4).
Publications