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Synthesis of Mo–W carbide via propane carburization of the precursor sulfide: Kinetic analysis
Author(s) -
Nguyen TuanHuy,
Adesina Adesoji A,
Yue Ernest MT,
Lee YongJoon,
Khodakov Andrei,
Brungs Michael P
Publication year - 2004
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.994
Subject(s) - thermogravimetric analysis , isothermal process , sulfide , activation energy , carbide , catalysis , propane , order of reaction , chemistry , atmospheric temperature range , kinetic energy , kinetics , reaction rate , metal , materials science , analytical chemistry (journal) , reaction rate constant , thermodynamics , organic chemistry , physics , quantum mechanics
Thermogravimetric analysis (TGA) has been used to investigate the carburization kinetics of Mo–W sulfide using an H 2 :C 3 H 8 feed mixture. The effect of heating rate over the range 1–10 K min −1 showed that up to four different carburized products may be formed but the critical (peak) temperature for formation of these species and the amount (peak height) of each species formed are highly dependent on the heating rate employed. The critical temperature increased linearly with heating rate for each of the four products. The four TGA peaks corresponding to the four phase transformation species are consistent with XRD identifiable species, namely; α‐Mo 2 C, β‐Mo 2 C, W and MoC 1− x . Isothermal conversion–time data at three different temperatures are described by a reaction‐controlled shrinking core model implicating a first‐order dependency on the H 2 :C 3 H 8 ratio. The reaction exhibited fractional order dependence on the metal sulfide concentration, the associated global activation energy estimated as 227 kJ mol −1 is representative of a non‐catalytic gas–solid reaction. Copyright © 2004 Society of Chemical Industry