微波辐射下NO转化的研究
摘要
微波辐射辅助催化技术涉及微波加热和微波放电两个方面。前者在有机化
学反应中被大量研究，获得了许多有意义的结果。然而关于后者的研究迄今为
止基本上是个空白。本论文以多相催化反应为出发点，以富氧条件下NO转化
为探针反应，研究了微波辐射技术与催化技术的偶合作用。
首次研究了微波放电辅助催化CH_4还原NO。结果发现在Ni（10％）/HZSM-5
催化剂上，微波放电可使NO几乎100％转化，而且使反应所需温度大幅度下降，
通过对反应结果的分析得出了微波放电辅助催化的可能原因。进一步通过使用
特殊的反应器，首次研究了常压下微波放电直接分解NO，利用此技术可以将近
90％的NO一步分解为环境友好的N_2。随后探讨了各种反应参数变化对NO转化的
影响，分析了此反应机理，得出了微波放电的优点在于气相直接活化反应物。
在上面研究的基础上，接着观察了微波加热对催化反应的影响。发现微波
加热辅助催化CH_4还原NO能够明显的增大催化剂的活性温度区间，降低反应
所需温度。进一步利用微波加热技术，首次研究了微波加热辅助催化直接分解
NO。结果在Fe/NaZSM-5催化剂上，实现了70％NO一步直接转化为N_2，而且
催化剂显示了较好的O_2适应能力。通过分析催化剂与微波作用机理，将催化剂
在微波加热下形成的局部热点与催化剂的活性位实现了有机的统一。利用
FTIR、MBS和XPS等表征技术，对试前和试后催化剂的状态进行了分析，得
出微波加热催化分解NO的可能机理，阐述了微波加热在辅助催化反应中的三
个重要作用，其中立足点是局部热点效应。
最后，首次将微波加热辅助催化技术应用到净化模拟汽车尾气方面，发现
此方法具有降低催化剂起活温度，增大空燃比窗口等特点。
Microwave irradiation assisted catalysis consists of microwave heating assisted
catalysis and microwave discharge assisted catalysis. The former has been
investigated extensively in organic chemistry, and novel results have been obtained.
However, few reports have been focused on the catalysis by microwave discharge. In
the present dissertation, the effects of coupling microwave irradiation and catalysis
on catalytic reduction of NO were investigated.
For the first time, the microwave discharge assisted catalytic reduction of NO by
CH4 was investigated. The conversion of NO to N2 was approximately 100% over a
Ni( I 0%)IHZSM-5 catalyst by this method, and the reaction temperature could be
lowered remarkably. By analyzing the reaction results, the possible action of the
method is suggested. Furthermore, the microwave discharge decomposition of NO
was investigated for the first time with a special reactor at atmospheric pressure. The
one-step conversion of NO to N2 approximated to 9O扸o by this method. The effects of
various reaction parameters on NO conversion were also studied. By analyzing the
reaction mechanisms, it is drawn that the advantage of microwave discharge is the
direct activating of the reactants in the gas phase.
Then, the effects of microwave heating on the catalytic reaction were studied.
The results showed that the range of the active temperature was widened clearly and
the temperature for running the catalytic reaction could be lowered when the
reduction of NO by CH4 was assisted by microwave heating. Furthermore, the
catalytic decomposition of NO assisted by microwave heating was also investigated
for the first time. The conversion of NO to N2 was up to 70% by microwave heating
over an Fe/NaZSM-5 catalyst. The tolerance of 02 was better for the catalyst under
such conditions. The local heating sites formed by microwave heating were
identified to be catalytic active sites. The reaction mechanism was discussed basing
Ill
on characterization results of the catalysts by FTIR~ MBS and XPS, etc., before and
after the experiments. The action of microwave heating on the catalytic
decomposition of NO involved three factors which were related on the local heating
effects.
Finally, it was observed for the first time that the automotive emission could be
purified by the microwave heating assisted catalytic method. The results showed that
the method could widen the air/fuel ratio window of the catalyst and lower the
light-off temperature.
学反应中被大量研究，获得了许多有意义的结果。然而关于后者的研究迄今为
止基本上是个空白。本论文以多相催化反应为出发点，以富氧条件下NO转化
为探针反应，研究了微波辐射技术与催化技术的偶合作用。
首次研究了微波放电辅助催化CH_4还原NO。结果发现在Ni（10％）/HZSM-5
催化剂上，微波放电可使NO几乎100％转化，而且使反应所需温度大幅度下降，
通过对反应结果的分析得出了微波放电辅助催化的可能原因。进一步通过使用
特殊的反应器，首次研究了常压下微波放电直接分解NO，利用此技术可以将近
90％的NO一步分解为环境友好的N_2。随后探讨了各种反应参数变化对NO转化的
影响，分析了此反应机理，得出了微波放电的优点在于气相直接活化反应物。
在上面研究的基础上，接着观察了微波加热对催化反应的影响。发现微波
加热辅助催化CH_4还原NO能够明显的增大催化剂的活性温度区间，降低反应
所需温度。进一步利用微波加热技术，首次研究了微波加热辅助催化直接分解
NO。结果在Fe/NaZSM-5催化剂上，实现了70％NO一步直接转化为N_2，而且
催化剂显示了较好的O_2适应能力。通过分析催化剂与微波作用机理，将催化剂
在微波加热下形成的局部热点与催化剂的活性位实现了有机的统一。利用
FTIR、MBS和XPS等表征技术，对试前和试后催化剂的状态进行了分析，得
出微波加热催化分解NO的可能机理，阐述了微波加热在辅助催化反应中的三
个重要作用，其中立足点是局部热点效应。
最后，首次将微波加热辅助催化技术应用到净化模拟汽车尾气方面，发现
此方法具有降低催化剂起活温度，增大空燃比窗口等特点。
Microwave irradiation assisted catalysis consists of microwave heating assisted
catalysis and microwave discharge assisted catalysis. The former has been
investigated extensively in organic chemistry, and novel results have been obtained.
However, few reports have been focused on the catalysis by microwave discharge. In
the present dissertation, the effects of coupling microwave irradiation and catalysis
on catalytic reduction of NO were investigated.
For the first time, the microwave discharge assisted catalytic reduction of NO by
CH4 was investigated. The conversion of NO to N2 was approximately 100% over a
Ni( I 0%)IHZSM-5 catalyst by this method, and the reaction temperature could be
lowered remarkably. By analyzing the reaction results, the possible action of the
method is suggested. Furthermore, the microwave discharge decomposition of NO
was investigated for the first time with a special reactor at atmospheric pressure. The
one-step conversion of NO to N2 approximated to 9O扸o by this method. The effects of
various reaction parameters on NO conversion were also studied. By analyzing the
reaction mechanisms, it is drawn that the advantage of microwave discharge is the
direct activating of the reactants in the gas phase.
Then, the effects of microwave heating on the catalytic reaction were studied.
The results showed that the range of the active temperature was widened clearly and
the temperature for running the catalytic reaction could be lowered when the
reduction of NO by CH4 was assisted by microwave heating. Furthermore, the
catalytic decomposition of NO assisted by microwave heating was also investigated
for the first time. The conversion of NO to N2 was up to 70% by microwave heating
over an Fe/NaZSM-5 catalyst. The tolerance of 02 was better for the catalyst under
such conditions. The local heating sites formed by microwave heating were
identified to be catalytic active sites. The reaction mechanism was discussed basing
Ill
on characterization results of the catalysts by FTIR~ MBS and XPS, etc., before and
after the experiments. The action of microwave heating on the catalytic
decomposition of NO involved three factors which were related on the local heating
effects.
Finally, it was observed for the first time that the automotive emission could be
purified by the microwave heating assisted catalytic method. The results showed that
the method could widen the air/fuel ratio window of the catalyst and lower the
light-off temperature.
引文
[1] K.C. Taylor, Catal. Rev. Sci. Eng., 1993, 35, 457．
[2] K. Hadjiivanov, D. Klissurski, G. Ramis, G. Busca, Appl. Catal. B, 1996, 7, 251．
[3] J.N. Armor, Environmental catalysis, Appl. Catal. B, 1992, 1, 221．
[4] G.L. Manney, L. Froidevaux, J.W. Waters, Nature, 1994, 20, 149．
[5] J.H. Seinfekd, Urban air pollution: State of the science, Science, 1989, 243, 745．
[6] T. Nakatsuji, A. Miyamoto, Catal. Today, 1991, 10, 21．
[7] C.J. Pereira, Catalysis and Surface Science, Marceldekker, Inc., New York, 1985．
[8] M. Iwamoto, Proceeding of meeting of catalytic technology for removal of nitrogen monoxide, Tokyo, Japan, 1990, 17．
[9] W. Held, A. Koening. T Richter, L. Puppe, SAE paper 900496, 1990．
[10] Y. Li, J.N. Armor, Appl. Catal. B, 1992, 1,131．
[11] M. Iwamoto, H. Furukawa, Y. Mine, F. Uemura, S. Mikuriua, S. Kagawa, J. Chem. Soc., Chem. Commun., 1986, 1272．
[12] 王真，吉林大学博士论文，长春，1996．
[13] 微波化学，金钦汉，科学出版社，1999．
[2] K. Hadjiivanov, D. Klissurski, G. Ramis, G. Busca, Appl. Catal. B, 1996, 7, 251．
[3] J.N. Armor, Environmental catalysis, Appl. Catal. B, 1992, 1, 221．
[4] G.L. Manney, L. Froidevaux, J.W. Waters, Nature, 1994, 20, 149．
[5] J.H. Seinfekd, Urban air pollution: State of the science, Science, 1989, 243, 745．
[6] T. Nakatsuji, A. Miyamoto, Catal. Today, 1991, 10, 21．
[7] C.J. Pereira, Catalysis and Surface Science, Marceldekker, Inc., New York, 1985．
[8] M. Iwamoto, Proceeding of meeting of catalytic technology for removal of nitrogen monoxide, Tokyo, Japan, 1990, 17．
[9] W. Held, A. Koening. T Richter, L. Puppe, SAE paper 900496, 1990．
[10] Y. Li, J.N. Armor, Appl. Catal. B, 1992, 1,131．
[11] M. Iwamoto, H. Furukawa, Y. Mine, F. Uemura, S. Mikuriua, S. Kagawa, J. Chem. Soc., Chem. Commun., 1986, 1272．
[12] 王真，吉林大学博士论文，长春，1996．
[13] 微波化学，金钦汉，科学出版社，1999．