We present a variety of X-ray techniques for a structural characterization of catalysts on the example of automotive three-way catalysts at ambient and non-ambient conditions.
X-ray techniques, such as X-ray diffraction (XRD) and fluorescence (XRF) small-angle X-ray scattering (SAXS) and X-ray scattering in combination with pair distribution function (PDF) analysis are often traditionally assigned to large- scale facilities, like synchrotrons and spallation neutron sources.
We demonstrate, however, that these methods can be combined on laboratory instruments (most of which even on one single XRD platform).
As a model system we present supported PdO nanoparticles on reducible oxides such as Co3O4 and γ-Fe2O3. Parameters and characteristics that can be extracted from the X-ray experiments are:
- Elemental composition
- Qualitive and quantitative phase composition
- Phase behavior and stability (in- situ heating and cooling experiments)
- Crystallite size and structure
- Particle size and shape, size distribution, specific surface area
- Short- and long- range atomic ordering