物理化学学报 >> 2008, Vol. 24 >> Issue (07): 1271-1276.doi: 10.3866/PKU.WHXB20080725

研究论文 上一篇    下一篇

CF4在Al2O3基金属氧化物上的分解反应

范杰; 徐秀峰; 牛宪军   

  1. 烟台大学应用催化研究所, 山东 烟台 264005
  • 收稿日期:2007-12-03 修回日期:2008-03-09 发布日期:2008-07-04
  • 通讯作者: 徐秀峰 E-mail:xxf@ytu.edu.cn

Decomposition of CF4 over Al2O3-Based Metal Oxides

FAN Jie; XU Xiu-Feng; NIU Xian-Jun   

  1. Institute of Applied Catalysis, Yantai University, Yantai 264005, Shandong Province, P. R. China
  • Received:2007-12-03 Revised:2008-03-09 Published:2008-07-04
  • Contact: XU Xiu-Feng E-mail:xxf@ytu.edu.cn

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摘要： 考察了在无水条件下γ-Al2O3基金属氧化物M-Al2O3(M=Mg、La、Ba、Ce、Ni、P)与CF4反应转化为金属氟化物的反应. 结果表明, 在所筛选的金属氧化物中, γ-Al2O3的初活性较高, 但由于CF4分解时产生的强放热效应使未反应的γ-Al2O3发生了α相变, 致使CF4转化率急剧下降, 反应温度越高, γ-Al2O3的α相变越快, 活性下降就越快. CF4在MgO-Al2O3上分解时, Mg物种比Al优先氟化生成了MgF2, Mg物种的氟化反应及其产生的强放热效应使MgAl2O4结构发生了解体. 在Al2O3表面负载助剂P、Ni,提高了其热稳定性, 抑制了CF4高温分解时未反应的Al2O3发生α相变, 使更多的γ-Al2O3参与了CF4分解反应.

关键词: CF4分解, Al2O3, γ-Al2O3的α相变, 改性Al2O3

Abstract: The decomposition of CF4 in the absence of water on γ-Al2O3-based metal oxides was carried out to destruct the disposal perfluoro-carbons (PFCs) from industrial processes. In the present work, the conversion of CF4 was tested over bare γ-Al2O3 at different temperatures of 825, 850 and 900 ℃. It was found that the initial activity of Al2O3 increased in the order of 825 ℃<850 ℃<900 ℃CO2 yield declined quickly with time on stream because the un-reacted γ-Al2O3 was transformed into inactive α-Al2O3 phase that resulted from the highly exothermic effect of Al2O3-fluorination reaction. As for the CF4 decomposition on MgO-Al2O3, fluorination of Mg species and the highly exothermic effect produced led to the collapse of MgAl2O4 structure, in which the magnesium element was fluorinated into MgF2. Al2O3 modified with P or Ni could inhibit the transformation of un-reacted γ-Al2O3 into α-Al2O3 during CF4 decomposition, and consequently CF4 conversion reached a stable level with time on stream.

Key words: CF4 decomposition, Al2O3, Transformation of γ-Al2O3 into α-Al2O3, Modified Al2O3

MSC2000: 

  • O643.3