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Synthesis, characterization, and reactivity of tungsten oxynitride

Published online by Cambridge University Press:  31 January 2011

Toby E. Lucy
Affiliation:
Environmental Catalysis and Materials Laboratory, Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061–0211
Todd P. St. Clair
Affiliation:
Environmental Catalysis and Materials Laboratory, Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061–0211
S. Ted Oyama
Affiliation:
Environmental Catalysis and Materials Laboratory, Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061–0211
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Abstract

High surface area tungsten oxynitride has been prepared by the temperature programmed reaction (TPR) of WO3 with NH3. All samples were characterized by x-ray diffraction (XRD), nitrogen physisorption, CO chemisorption, and elemental analysis. Samples were prepared at different heating rates (β), and a Redhead analysis yielded an activation energy for nitridation of 109 kJ mol−1. A heating rate of 0.016 K s−1 gave optimal synthesis conditions. Solid state intermediates were studied by interrupting the temperature program at various stages. No distinct suboxide phases were found using XRD. The nitridation step was determined to be a continuous transformation from oxide to oxynitride. Surface area, CO uptake, and nitrogen weight % were all found to increase as the reaction progressed. Reactivity experiments showed reasonable hydrodeoxygenation (HDO) and hydrodenitrogenation (HDN) activity, but little hydrogenation (HYD) or hydrodesulfurization (HDS) activity.

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Articles
Copyright
Copyright © Materials Research Society 1998

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