title: Avalanching strain dynamics during the hydriding phase transformation in individual palladium nanoparticles.
abstract: Phase transitions in reactive environments are crucially important in energy and information storage, catalysis and sensors. Nanostructuring active particles can yield faster charging/discharging kinetics, increased lifespan and record catalytic activities. However, establishing the causal link between structure and function is challenging for nanoparticles, as ensemble measurements convolve intrinsic single-particle properties with sample diversity. Here we study the hydriding phase transformation in individual palladium nanocubes in situ using coherent X-ray diffractive imaging. The phase transformation dynamics, which involve the nucleation and propagation of a hydrogen-rich region, are dependent on absolute time (aging) and involve intermittent dynamics (avalanching). A hydrogen-rich surface layer dominates the crystal strain in the hydrogen-poor phase, while strain inversion occurs at the cube corners in the hydrogen-rich phase. A three-dimensional phase-field model is used to interpret the experimental results. Our experimental and theoretical approach provides a general framework for designing and optimizing phase transformations for single nanocrystals in reactive environments.
authors.affiliation: Department of Physics, University of California-San Diego, La Jolla, California 92093-0319, USA.|Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: A
authors.identifier: http://orcid.org/0000-0003-4611-2561
authors.initials: A
authors.lastname: Ulvestad
authors.affiliation: Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Welland
authors.affiliation: School of Chemistry &Bio21 Institute, University of Melbourne, Parkville, Victoria 3010, Australia.
authors.forename: S S E
authors.initials: SS
authors.lastname: Collins
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: R
authors.initials: R
authors.lastname: Harder
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: E
authors.initials: E
authors.lastname: Maxey
authors.affiliation: Department of Physics, University of California-San Diego, La Jolla, California 92093-0319, USA.
authors.forename: J
authors.initials: J
authors.lastname: Wingert
authors.affiliation: Department of Physics, University of California-San Diego, La Jolla, California 92093-0319, USA.
authors.forename: A
authors.initials: A
authors.lastname: Singer
authors.affiliation: Department of Nano Engineering, University of California-San Diego, La Jolla, California 92093-0319, USA.
authors.forename: S
authors.initials: S
authors.lastname: Hy
authors.affiliation: School of Chemistry &Bio21 Institute, University of Melbourne, Parkville, Victoria 3010, Australia.
authors.forename: P
authors.initials: P
authors.lastname: Mulvaney
authors.affiliation: Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: P
authors.initials: P
authors.lastname: Zapol
authors.affiliation: Department of Physics, University of California-San Diego, La Jolla, California 92093-0319, USA.
authors.forename: O G
authors.initials: OG
authors.lastname: Shpyrko