title: Revealing local variations in nanoparticle size distributions in supported catalysts: a generic TEM specimen preparation method.
abstract: The specimen preparation method is crucial for how much information can be gained from transmission electron microscopy (TEM) studies of supported nanoparticle catalysts. The aim of this work is to develop a method that allows for observation of size and location of nanoparticles deposited on a porous oxide support material. A bimetallic Pt-Pd/Al(2)O(3) catalyst in powder form was embedded in acrylic resin and lift-out specimens were extracted using combined focused ion beam/scanning electron microscopy (FIB/SEM). These specimens allow for a cross-section view across individual oxide support particles, including the unaltered near surface region of these particles. A site-dependent size distribution of Pt-Pd nanoparticles was revealed along the radial direction of the support particles by scanning transmission electron microscopy (STEM) imaging. The developed specimen preparation method enables obtaining information about the spatial distribution of nanoparticles in complex support structures which commonly is a challenge in heterogeneous catalysis.
authors.affiliation: Competence Centre for Catalysis (KCK), Department of Applied Physics, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden.
authors.forename: Torben
authors.initials: T
authors.lastname: Pingel
authors.affiliation: Competence Centre for Catalysis (KCK), Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Skoglundh
authors.affiliation: Competence Centre for Catalysis (KCK), Department of Applied Physics, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden.
authors.forename: Henrik
authors.initials: H
authors.lastname: Grönbeck
authors.affiliation: Competence Centre for Catalysis (KCK), Department of Applied Physics, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden.
authors.forename: Eva
authors.initials: E
authors.lastname: Olsson
keywords: FIB/SEM; TEM; palladium; platinum; specimen preparation; supported nanoparticle catalyst