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Synthesis of a Mo/Nb mixed carbide

Published online by Cambridge University Press:  31 January 2011

V. L. S. Teixeira da Silva
Affiliation:
NUCAT/PEQ/COPPE/Universidade Federal do Rio de Janeiro, Caixa Postal 68502, Rio de Janeiro, RJ-21945-970, Brazil, and Environmental Catalysis and Materials Laboratory, Department of Chemical Engineering, Virginia Polytechnic Institute & State University, Blacksburg, Virginia 24061
M. Schmal
Affiliation:
NUCAT/PEQ/COPPE/Universidade Federal do Rio de Janeiro, Caixa Postal 68502, Rio de Janeiro, RJ-21945-970, Brazil
V. Schwartz
Affiliation:
Environmental Catalysis and Materials Laboratory, Department of Chemical Engineering, Virginia Polytechnic Institute & State University, Blacksburg, Virginia 24061
S. T. Oyama
Affiliation:
Environmental Catalysis and Materials Laboratory, Department of Chemical Engineering, Virginia Polytechnic Institute & State University, Blacksburg, Virginia 24061
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Molybdenum and niobium carbides (β−Mo2C, NbC), as well as mixed carbides of molybdenum and niobium, were synthesized by the temperature-programmed carburization method (TPC) using a 20 vol% CH4/H2 gas mixture. The starting materials were MoO3, B-Nb2O5, and physical mixtures of B-Nb2O5/MoO3 with Nb/(Nb + Mo) atomic ratios varying from 0.2 to 0.8, respectively. Results from catalytic and temperatureprogrammed oxidation (TPO) measurements indicate that during the carburization of the Nb2O5/MoO3 physical mixture with Nby(Nb + Mo) = 0.8 there is, besides β−Mo2C and NbC formation, the appearance of a carbidic phase not detectable by x-ray diffraction (XRD). This phase appears to be highly active and selective for the dibenzothiophene hydrodesulfurization (HDS) reaction.

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Articles
Copyright
Copyright © Materials Research Society 1998

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