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Title: Neutron diffraction studies for realtime leaching of catalytic Ni

The leaching of Al from intermetallic samples of Nickel Aluminium alloys to form Raney-type nickel catalysts is widely used in the hydrogenation industry, however, little is known of the leaching process itself. In this study, the leaching of Al was measured in realtime, in situ, using the high-flux powder neutron diffractometer, D20, at the Institut Laue-Langevin. Despite the liberation of hydrogen and effervescent nature of the reaction the transformation of the dry powder phases into Raney-type Ni was determined. Samples produced by gas-atomisation were found to leach faster than those produced using the cast and crushed technique. Regardless of processing route of the precursor powder, the formation of spongy-Ni occurs almost immediately, while Ni{sub 2}Al{sub 3} and NiAl{sub 3} continue to transform over longer periods of time. Small-angle scattering and broadening of the diffraction peaks is an evidence for the formation of the smaller Ni particles. Understanding the kinetics of the leaching process will allow industry to refine production of catalysts for optimum manufacturing time while knowledge of leaching dynamics of powders produced by different manufacturing techniques will allow further tailoring of catalytic materials.
Authors:
;  [1] ;  [2] ;  [2] ;  [3] ; ;  [4]
  1. European Space Agency, Keplerlaan 1, 2201 AZ Noordwijk (Netherlands)
  2. (France)
  3. Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden (Netherlands)
  4. Institut Laue-Langevin, 6 rue Jules Horowitz, BP 156, 38042 Grenoble (France)
Publication Date:
OSTI Identifier:
22419887
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 3; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ALUMINIUM ALLOYS; CATALYSTS; HYDROGEN; KINETICS; NEUTRON DIFFRACTION; NICKEL; PARTICLES; PEAKS; POWDERS; SMALL ANGLE SCATTERING