Abstract: Characterizing the structural properties (strain gradients, chemical composition, crystal orientation, and defects) inside nanostructures is a grand challenge in materials science. Bragg coherent diffraction imaging (CDI) can be utilized to address this challenge for crystalline nanostructures. A resolution of the structural properties of less than 10 nm is achieved up to date. The capabilities of the Bragg CDI technique will be demonstrated on single nanoparticles for enhanced catalysis.
As an example, the Bragg CDI technique allows understanding the interplay among shape, size, strain, faceting, composition, and defects at the nanoscale. We will demonstrate that Bragg CDI on a single-particle model catalyst makes it possible to map its local strain/defect field and directly image strain buildup close to the facets. We will also show results obtained during in situ and operando Bragg CDI measurements during CO oxidation and H2 hydrogenation: it was possible to track a single particle in a gas-phase environment, to monitor its facet changes, and to measure its strain response to the gas reaction.
This technique opens pathways to determine and control the internal structure of nanoparticles to tune and optimize them during catalytic and other chemical reactions. This technique should benefit from a unique opportunity: the ESRF EBS Upgrade. This should revolutionize imaging by making it possible to map evolving physico-chemical processes in a slow-motion movie.