Dynamic nucleation and growth of Ni nanoparticles on high-surface area titania |
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Authors: | P Li J Liu PA Crozier |
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Institution: | a TEM Laboratory, Department of Earth and Planetary Sciences, University of New Mexico, MSCO3-2040, Northrop Hall, Albuquerque, NM 87131, USA b Monsanto Company, 800 N. Lindbergh Boulevard, St. Louis, MO 63167, USA c Process Technology Group, Engelhard Corporation, 23800 Mercantile Road, Beachwood, OH 44122, USA d Center for Solid State Science, Arizona State University, Tempe, AZ 85287-1704, USA |
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Abstract: | Nucleation and growth mechanisms of Ni nanoparticles synthesized via an incipient wetness technique on a high-surface area titania support (i.e., a mixture of anatase and rutile) are studied using environmental transmission electron microscope (ETEM). Most Ni nanoparticles are found to nucleate from the Ni precursor coated on the surface of the titania support. Even though both anatase and rutile supports are the nucleation sites for Ni nanoparticles, it was observed that the particles have different morphologies on the supports, i.e., a non-wetting morphology on the anatase support versus a wetting morphology on the rutile {1 0 1}. This is because the interfacial energy of Ni/rutile is lower than that of Ni/anatase. Titania clusters are found to nucleate on the surface of the Ni particles during in situ ETEM reduction, indicating that the presence of partial titania overlayers is directly related to the synthesis of the Ni/TiO2 catalysts. The growth mode of the Ni nanoparticles on the titania support is three-dimensional, while that of the rutile cluster on the surface of the Ni is two-dimensional layer-by-layer. |
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Keywords: | Ni Titanium oxide Anatase Rutile Nucleation Growth Morphology Reduction Synthesis Environmental TEM Nanoparticles Catalysts |
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