title: Tomographic heating holder for in situ TEM: study of Pt/C and PtPd/Al2O3 catalysts as a function of temperature.
abstract: A tomographic heating holder for transmission electron microscopy that can be used to study supported catalysts at temperatures of up to ~1,500°C is described. The specimen is placed in direct thermal contact with a tungsten filament that is oriented perpendicular to the axis of the holder without using a support film, allowing tomographic image acquisition at high specimen tilt angles with minimum optical shadowing. We use the holder to illustrate the evolution of the active phases of Pt nanoparticles on carbon black and PtPd nanoparticles on γ-alumina with temperature. Particle size distributions and changes in active surface area are quantified from tilt series of images acquired after subjecting the specimens to increasing temperatures. The porosity of the alumina support and the sintering mechanisms of the catalysts are shown to depend on distance from the heating filament.
authors.affiliation: 1Instituto de Ciencia de Materiales de Sevilla (CSIC),41092,Sevilla,Spain.
authors.forename: Lionel C
authors.initials: LC
authors.lastname: Gontard
authors.affiliation: 2Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C) and Peter Grünberg Institute (PGI),Forschungszentrum Jülich,D-52425 Jülich,Germany.
authors.forename: Rafal E
authors.initials: RE
authors.lastname: Dunin-Borkowski
authors.affiliation: 1Instituto de Ciencia de Materiales de Sevilla (CSIC),41092,Sevilla,Spain.
authors.forename: Asunción
authors.initials: A
authors.lastname: Fernández
authors.affiliation: 3Johnson Matthey Technology Centre,Blount's Court,Sonning Common,Reading RG4 9NH,UK.
authors.forename: Dogan
authors.initials: D
authors.lastname: Ozkaya
authors.affiliation: 4Center for Electron Nanoscopy,Technical University of Denmark,DK-2800 Kgs. Lyngby,Denmark.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kasama