5D operando tomographic diffraction imaging of a catalyst bed.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30420610.
- Also identified by DOI 10.1038/s41467-018-07046-8 and PMC identifier 6232103.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
We report the results from the first 5D tomographic diffraction imaging experiment of a complex Ni-Pd/CeO<sub>2</sub>-ZrO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> catalyst used for methane reforming. This five-dimensional (three spatial, one scattering and one dimension to denote time/imposed state) approach enabled us to track the chemical evolution of many particles across the catalyst bed and relate these changes to the gas environment that the particles experience. Rietveld analysis of some 2 × 10<sup>6</sup> diffraction patterns allowed us to extract heterogeneities in the catalyst from the Å to the nm and to the μm scale (3D maps corresponding to unit cell lattice parameters, crystallite sizes and phase distribution maps respectively) under different chemical environments. We are able to capture the evolution of the Ni-containing species and gain a more complete insight into the multiple roles of the CeO<sub>2</sub>-ZrO<sub>2</sub> promoters and the reasons behind the partial deactivation of the catalyst during partial oxidation of methane.