《Co_paper》.pdf

Catal Lett (2011) 141:754–761 DOI 10.1007/s10562-011-0600-8 In-Situ Reduction of Promoted Cobalt Oxide Supported on Alumina by Environmental Transmission Electron Microscopy Roya Dehghan • Thomas W. Hansen • Jakob B. Wagner • Anders Holmen • Erling Rytter • Øyvind Borg • John C. Walmsley Published online: 2 May 2011 The Author(s) 2011. This article is published with open access at S Abstract Reduction of 12wt.%Co/0.5wt.%Re/a-Al O Keywords Environmental transmission electron 2 3 Fischer–Tropsch catalyst has been studied in-situ in an microscopy Fischer–Tropsch In-situ Reduction Cobalt environmental transmission electron microscope. Reduction of Co3O4 to metallic cobalt was observed dynamically at 360 C under 3.4 mbar H2. Structural and morphological 1 Introduction changes were observed by high resolution transmission electron microscopy and scanning transmission electron Cobalt nanoparticles on a porous support, typically alu- microscopy imaging. The cobalt particles were mainly face mina, are widely used in Fischer–Tropsch (FT) processes centred cubic while some hexagonal close packed particles to convert natural gas into synthetic fuel. To optimize the were also found. Reoxidation of the sample upon cooling to efficiency of these catalysts and the FT process, a funda- room temperature, still under flowing H2, underlines the mental understanding of the catalyst structure and behav- reactivity of the nanoparticles and the importance of con- iour must be obtained on the nanometre scale [ 1]. trolling the gas composition and specimen temperature Dispersion, morphology and distribution of the particles durin