Marie-Ingrid Richard1 2 Sara Fernandez3 Lu Gao4 Jérôme Carnis1 Jan Philipp Hofmann4 Stephane Labat1 Steven Leake2 Tobias Schulli5 Olivier Thomas1

1, IMN2P, Grenoble, , France
2, ESRF, Grenoble, , France
3, Paul Scherrer Institut, Villigen, , Switzerland
4, Laboratory of Inorganic Materials Chemistry, Eindhoven, , Netherlands
5, ESRF, Grenoble, , Cuba

Characterising the structural properties (strain gradients, chemical composition, crystal orientation and defects) inside nanostructures is a grand challenge in materials science. Bragg coherent diffraction imaging (Bragg 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 [1]. The capabilities of the Bragg CDI technique will be demonstrated on single nanoparticles during thermal annealing and for enhanced catalysis. The experiments have been performed at the beamline ID01 at The European Synchrotron (ESRF), where a Fresnel zone-plate was used to focus the beam with energy of 8 keV to a spotsize of 100 nm (V) × 300 (H) nm2.
The Bragg CDI technique allows understanding the interplay between shape, size, strain, faceting [2], composition and defects at the nanoscale. For example, we will demonstrate that Bragg CDI on a single particle model catalyst makes it possible to map its local strain/defect field and directly images strain build-up close to the facets. The localized strain modifies sorption energies of the reactants. In situ [3] and operando Bragg CDI was also performed: it was possible to track a single particle in gas phase environment, to monitor its facet changes and to measure its strain response to gas.
This technique opens pathways to determine and control the internal structure of nanoparticles to tune and optimize them during catalytic and other chemical reactions.

[1] S. Labat, M.-I. Richard, M. Dupraz, M. Gailhanou, G. Beutier, M. Verdier, F. Mastropietro, T. W. Cornelius, T. U. Schülli, J. Eymery, and O. Thomas, ACS Nano 9, 9210 (2015).
[2] M.-I. Richard, S. Fernandez, J. Eymery, J.-P. Hofmann, L. Gao, J. Carnis, S. Labat, V. Favre-Nicolin, E. J. M. Hensen, O. Thomas, T. Schülli, and S. J. Leake, Submitted (2017).
[3] M.-I. Richard, S. Fernández, J. P. Hofmann, L. Gao, G. A. Chahine, S. J. Leake, H. Djazouli, Y. De Bortoli, L. Petit, P. Boesecke, S. Labat, E. J. M. Hensen, O. Thomas, and T. Schülli, Rev. Sci. Instrum. 88, 093902 (2017).