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Low Effective Activation Energies for Oxygen Release from Metal Oxides: Evidence for Mass‐Transfer Limits at High Heating Rates
Author(s) -
Jian Guoqiang,
Zhou Lei,
Piekiel Nicholas W.,
Zachariah Michael R.
Publication year - 2014
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201301148
Subject(s) - thermite , oxygen , activation energy , chemistry , metal , combustion , mass transfer , decomposition , oxide , chemical engineering , mass spectrometry , thermal decomposition , analytical chemistry (journal) , reaction rate , materials science , inorganic chemistry , environmental chemistry , organic chemistry , chromatography , engineering , catalysis
Oxygen release from metal oxides at high temperatures is relevant to many thermally activated chemical processes, including chemical‐looping combustion, solar thermochemical cycles and energetic thermite reactions. In this study, we evaluated the thermal decomposition of nanosized metal oxides under rapid heating (∼10 5 K s −1 ) with time‐resolved mass spectrometry. We found that the effective activation‐energy values that were obtained using the Flynn–Wall–Ozawa isoconversional method are much lower than the values found at low heating rates, indicating that oxygen transport might be rate‐determining at a high heating rate.