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"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"相变,使更多的γ-Al2O3参与了CF4分解反应.
The decomposition of CF4 in the absence of water on γ-Al2O3-based metal oxides was carded 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 A1203 increased in the order of 825 ℃〈850 ℃〈900 ℃, unfortunately the 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.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2008年第7期1271-1276,共6页
Acta Physico-Chimica Sinica
基金
国家自然科学基金(20573089)
山东省教育厅科技计划(J05D04)资助项目
