Doped Perovskites To Evaluate the Relationship between Fuel–Oxidizer Thermite Ignition and Bond Energy, Electronegativity, and Oxygen Vacancy

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• 作者：Xizheng Wang ; Tao Wu ; Michael R. Zachariah
• 刊名：Journal of Physical Chemistry C
• 出版年：2017
• 出版时间：January 12, 2017
• 年：2017
• 卷：121
• 期：1
• 页码：147-152
• 全文大小：409K
• ISSN：1932-7455

文摘

Despite our knowledge of the existence of the violent thermite reaction for over 100 years, it is still not yet understood how the properties of a metal oxide oxidizer relate to and influence the ignition temperature. To address this shortcoming, we prepared a series of perovskite-based oxidizers which enable a systematic investigation of how materials properties of the oxidizer relate to the ignition temperature. In this paper, nine lanthanum-based perovskites with different Srp>2+p> doping of the A-site and different B-site transition metals were synthesized. The perovskite O₂ release and ignition temperatures with aluminum were measured by fast heating (>10p>5p> K/s) temperature-jump/time-of-flight mass spectrometry coupled with high-speed imaging. These results were then correlated with the average bond energy and overall metal–oxygen electronegativity difference. Remarkably, we found a linear relationship between average bond energy and electronegativity with ignition temperature. To our knowledge this is the first demonstration of the connection between metal–oxygen bond energy, electronegativity, and ignition temperature.