Neutron studies of nanostructured CuO-Al{sub 2}O{sub 3} NOx removal catalysts

Conference · Mon Jul 14 04:00:00 EDT 1997

OSTI ID:561224

Ozawa, Masakuni ^[1]; Chun-Keung, Loong ^[2]

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1. Nagoya Institute of Technology, Tajimi (Japan)
2. Argonne National Lab., IL (United States)

Nanostructured powders of automotive catalytic system CuO0Al{sub 2}O{sub 3}, targeted for nitrogen oxides (NOx) removal under lean-burn engine conditions, were investigated using neutron diffraction and small-angle neutron scattering. The crystal phases, structural transformations and microstructure of 10 mol% Cu-Al{sub 2}O{sub 3} powders are characterized according to the heat-treatment conditions. These properties are correlated with the pore structure and NOx removal efficiency determined by nitrogen adsorption isotherm, electron spin resonance, and temperature programmed reaction measurements. The {gamma}-(Cu, Al){sub 2}O{sub 3} phase and the mass-fractal-like aggregate of particles (size {approx} 26 nm) at annealing temperatures below 900{degrees}C were found to be crucial to the high NOx removal performance. The transformation to bulk crystalline phases of {alpha}-Al{sub 2}O{sub 3} + CuAl{sub 2}O{sub 4} spinel above {approximately}1050{degrees}C corresponds to a drastic drop of Nox removal efficiency. The usefulness of neutron-scattering techniques as well as their complementarity with other traditional methods of catalytic research are discussed.

• Research Organization: Argonne National Lab., IL (United States)
• Sponsoring Organization: USDOE Office of Energy Research, Washington, DC (United States)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 561224
• Report Number(s): ANL/IPNS/CP--94279; CONF-970814--; ON: DE97054136
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
36 MATERIALS SCIENCE
AIR POLLUTION CONTROL
ALUMINIUM OXIDES
ANNEALING
CATALYSTS
COPPER OXIDES
ELECTRON SPIN RESONANCE
EXHAUST GASES
MICROSTRUCTURE
NEUTRON DIFFRACTION
NITROGEN OXIDES
PHASE TRANSFORMATIONS
PORE STRUCTURE
POWDERS