由於工商業的蓬勃發展，間接使得機動車數量快速增加，而機動車引擎運轉時會產生氮氧化物(NOX)、碳氫化合物(HC)及一氧化氮(CO)等有害氣體，導致許多空氣污染的問題產生，所以許多國家都會以法規管制機動車的廢氣排放。為了改善機動車排放的廢氣污染情形，常見的解決方法是在機動車排氣管中加裝可以降低HC、CO、及NOX排放量的三向觸媒轉化器(Three way catalyst converter, TWC)。一般的三向觸媒轉化器主要是以鉑（Pt）或鈀（Pd）來催化氧化反應，以銠（Rh）來催化還原反應。然而，此一型態的觸媒是以貴重金屬為材料，故會有高成本及低熱穩定性的缺點。隨著廢氣排放法規越來越嚴格，在三向觸媒轉化器中貴重金屬的比例也越來越高，這使得尋找新形態的觸媒替代材料也變得越趨重要。
具有高熱穩定性以及優良氧化還原能力的鈣鈦礦氧化物被認為是有發展性的觸媒替代材料，但鈣鈦礦型觸媒的工作機制仍不明確。因此本研究的目標即是製造出一鈣鈦礦型觸媒並探究鈣鈦礦型觸媒的脫硝工作機制以及思考製程條件不同(如:材料合成鍛燒溫度、化學組成中部份元素置換)對鈣鈦礦觸媒材料的脫硝催化性能影響。
本研究以檸檬酸法合成鈣鈦礦氧化物La1-XSrXCoO3-δ(LSC, X=0, 0.2, 0.4, 0.6)，並將LSC鈣鈦礦粉末以XRD、SEM、BET、XPS、FT-TR及脫硝催化活性測試來瞭解鈣鈦礦型觸媒的工作機制及製程對鈣鈦礦觸媒材料的脫硝催化性能影響。結果顯示了本研究成功以檸檬酸法合成了奈米等級(粒徑約20nm)的鈣鈦礦氧化物。在脫硝催化活性測試中，其脫硝催化活性呈現了La0.8Sr0.2CoO3-δ > La0.6Sr0.4CoO3-δ > LaCoO3-δ > La0.4Sr0.6CoO3-δ的趨勢。從XPS的分析中可看出適量的鍶摻雜(X=0.2)可增進LSC表面未飽和的金屬氧化物鍵結濃度，這表示在LSC的表面可以擁有更多的氣體吸附位，使得催化活性可以進一步提升。然而過量的鍶摻雜會因為非晶質的第二相產生使得氣體吸附位減少，使得催化活性下降。LSC的脫硝催化過程可以稀燃NOx捕集技術說明，一氧化氮在LSC表面金屬離子的幫助下，氧化形成二氧化氮，並以亞硝酸或硝酸鹽類的形式吸附於LSC表面，當硝酸鹽及亞硝酸鹽與還原氣體如：HC、CO反應，才被還原成氮氣及氧氣。研究發現脫硝活性的能力與吸附位息息相關，且材料本身比表面積以及高價離子將左右脫硝活性的能力。
本研究以含浸法將LSC漿料批覆於不銹鋼載體上製備出鈣鈦礦型觸媒。製備出的鈣鈦礦觸媒在摩托車上做實車測試，其結果揭示了當摩托車處於待速狀態其脫硝轉化效率約為72%。本研究確定了LSC型觸媒的脫硝催化活性及實際使用可能性。

The nitrogen oxide (NOX) is kind of air pollutant formed during the combustion process. It is considered one of the dangerous pollutants because of it caused the acid rain and photochemical smog which were endangering human’s body. According to the research of World Health Organization, the lung cancer risk increases with diesel exhaust exposure that contains NOX. Thus it is important to reduce the amount of NOX to protect our environment and human’s health. The three ways catalytic converter with noble metal based is a common way of treating poisonous gases like HC, CO and NOX in exhaust. However, noble metal catalysts have disadvantages such as high cost and low thermal stability. Hence, it is necessary to find an alternative to noble metal based catalyst.
Perovskite oxides are believed as a potential catalytic material which may replace noble metal catalysts due to their low cost, high thermal stability and excellent redox reaction properties. But the de-NOX mechanism of perovskite oxides is still unclear. Hence, the aims of this thesis were explore the de-NOX mechanism of perovskite oxides, figure out the relationship between the de-NOX catalytic activity and synthesis method of the perovskite oxide and manufacture a perovskite-type catalyst. In this thesis, the perovskite-type oxides La1-XSrXCoO3-δ (LSC) which prepared by citric acid method were used to investigate the de-NOX mechanism of perovskite oxides and the partial replacement of the A-site ions effect on the de-NOX catalytic activity(X=0, 0.2, 0.4, 0.6). The LSC were characterized by XRD, SEM, XPS, FT-IR, and catalytic activity test. The results indicated that the LSC powders with particle size of 20 nm have been successfully synthesized by the citric acid method. The result of NO catalytic activity in the order such as La0.8Sr0.2CoO3-δ > La0.6Sr0.4CoO3-δ > LaCoO3-δ > La0.4Sr0.6CoO3-δ is revealed. The doping of Sr could not only increase the conceration of Co4+ but also enhance the number of NOX storage site with the improvement of the catalytic properties. When the concentration of Sr was greater than 0.4, the NOX storage sites were suppressed due to the result of charge balance and amorphous secondary phase. These lead to deterioration of the catalytic properties. Based on the analysis, the mechanism of de-NOX on LSC is proposed based on the lean NOX trap (LNT) model. The NO was oxidized to NOX that was stored on the surface of LSC in the form of nitrites and nitrates during the lean burn operation (oxidation condition). When the atmosphere became fuel-rich (reducing condition), the nitrites and nitrates were released and reduced to N2. Since the NOX storage/release was highly dependent on the active site. The amount of surface area, oxygen vacancies and the high valence metal cations must be increase.
The perovskite-type catalyst had been fabricated. The NO conversion performance of the perovskite-type catalyst can be compared to the traditional catalyst in motorcycle testing (the conversion efficiency of LSC type catalyst was 72% and traditional catalyst was 52% while the motorcycle was idling). It seems that the LSC type catalyst has the potential to become a great catalyst for vehicle application.

1. Russell, A.G., G.J. Mcrae, and G.R. Cass, The Dynamics of Nitric-Acid Production and the Fate of Nitrogen-Oxides. Atmospheric Environment, 1985. 19(6): p. 893-903.
2. Rowat, S.C., Incinerator toxic emissions: a brief summary of human health effects with a note on regulatory control. Medical Hypotheses, 1999. 52(5): p. 389-396.
3. Triebswetter, U. and T. Rave, NOxRegulation and Environmental Technological Change in the Glass Industry: A Case Study Based on Patent Evidence on NOxPrimary Measures from the EU and USA. Environmental Policy and Governance, 2013. 23(2): p. 104-117.
4. Kašpar, J., P. Fornasiero, and N. Hickey, Automotive catalytic converters: current status and some perspectives. Catalysis Today, 2003. 77(4): p. 419-449.
5. Takeuchi, M. and S. Matsumoto, NOx storage-reduction catalysts for gasoline engines. Topics in Catalysis, 2004. 28(1-4): p. 151-156.
6. Johnson, T.V., Review of diesel emissions and control. International Journal of Engine Research, 2009. 10(5): p. 275-285.
7. Cant, N.W. and M.J. Patterson, The storage of nitrogen oxides on alumina-supported barium oxide. Catalysis Today, 2002. 73(3-4): p. 271-278.
8. Mahzoul, H., J.F. Brilhac, and P. Gilot, Experimental and mechanistic study of NO(x) adsorption over NO(x) trap catalysts. Applied Catalysis B-Environmental, 1999. 20(1): p. 47-55.
9. Prinetto, F., et al., FT-IR and TPD investigation of the NOx storage properties of BaO/Al2O3 and Pt-BaO/Al2O3 catalysts. Journal of Physical Chemistry B, 2001. 105(51): p. 12732-12745.
10. Qi, G.S. and W. Li, Pt-free, LaMnO3 based lean NOx trap catalysts. Catalysis Today, 2012. 184(1): p. 72-77.
11. Yin, F., et al., Preparation and characterization of LaFe1−xMgxO3/Al2O3/FeCrAl: Catalytic properties in methane combustion. Applied Catalysis B: Environmental, 2006. 66(3-4): p. 265-273.
12. Qi, A., et al., La–Ce–Ni–O monolithic perovskite catalysts potential for gasoline autothermal reforming system. Applied Catalysis A: General, 2005. 281(1-2): p. 233-246.
13. Kim, C.H., et al., Strontium-Doped Perovskites Rival Platinum Catalysts for Treating NOx in Simulated Diesel Exhaust. Science, 2010. 327(5973): p. 1624-1627.
14. Epling, W.S., et al., Overview of the fundamental reactions and degradation mechanisms of NOx storage/reduction catalysts. Catalysis Reviews-Science and Engineering, 2004. 46(2): p. 163-245.
15. Fridell, E., et al., NOx storage in barium-containing catalysts. Journal of Catalysis, 1999. 183(2): p. 196-209.
16. Mahzoul, H., J.F. Brilhac, and P. Gilot, Experimental and mechanistic study of NOx adsorption over NOx trap catalysts. Applied Catalysis B: Environmental, 1999. 20(1): p. 47-55.
17. Olsson, L., et al., Mean field modelling of NOx storage on Pt/BaO/Al(2)O3. Catalysis Today, 2002. 73(3-4): p. 263-270.
18. Benowitz, N. and D. Dempsey, Pharmacotherapy for smoking cessation during pregnancy. Nicotine Tob Res, 2004. 6 Suppl 2: p. S189-202.
19. Holynska, B., et al., Study of the deterioration of sandstone due to acid rain and humid SO2 gas. X-Ray Spectrometry, 2004. 33(5): p. 342-348.
20. Mochida, I., et al., Removal of SOx and NOx over activated carbon fibers. Carbon, 2000. 38(2): p. 227-239.
21. Nimmo, W., et al., Simultaneous reduction of NOx and SO2 emissions from coal combustion by calcium magnesium acetate. Fuel, 2004. 83(2): p. 149-155.
22. Leibensperger, E.M., et al., Climatic effects of 1950-2050 changes in US anthropogenic aerosols - Part 1: Aerosol trends and radiative forcing. Atmospheric Chemistry and Physics, 2012. 12(7): p. 3333-3348.
23. Likens, G.E. and F.H. Bormann, Acid rain: a serious regional environmental problem. Science, 1974. 184(4142): p. 1176-9.
24. Kozioł, M.J. and F.R. Whatley, Gaseous air pollutants and plant metabolism. 1984, London ; Boston: Butterworths. xiv, 466 p.
25. Park, C.C., ES Books: Acid Rain: Rhetoric and Reality. Environ Sci Technol, 1988. 22(12): p. 1402.
26. Canadian Council of Ministers of the Environment. Climate Change Indicators Task Group., Climate, nature, people : indicators of Canada's changing climate. 2003, Winnipeg, Man.: Canadian Council of Ministers of the Environment. 45 p.
27. Faiz, A., C.S. Weaver, and M.P. Walsh, Air pollution from motor vehicles : standards and technologies for controlling emissions. 1996, Washington, D.C.: World Bank. xix, 246 p.
28. Climate Change 2007: The Physical Science Basis. South African Geographical Journal, 2009. 91(2): p. 103-103.
29. Koltsakis, G.C. and A.M. Stamatelos, Catalytic automotive exhaust aftertreatment. Progress in Energy and Combustion Science, 1997. 23(1): p. 1-39.
30. Tian, J.Y. and J.S. Lu, PREPARATION AND PROPERTIES OF NANOPHASE (Ce, Zr, Pr)O-2-DOPED ALUMINA COATING ON CORDIERITE CERAMIC HONEYCOMB FOR THREE-WAY CATALYSTS. Brazilian Journal of Chemical Engineering, 2012. 29(1): p. 121-133.
31. Bravo, J., et al., Wall coating of a CuO/ZnO/Al2O3 methanol steam reforming catalyst for micro-channel reformers. Chemical Engineering Journal, 2004. 101(1-3): p. 113-121.
32. Nijhuis, T.A., et al., Preparation of monolithic catalysts. Catalysis Reviews-Science and Engineering, 2001. 43(4): p. 345-380.
33. Bera, P., et al., Promoting effect of CeO2 in combustion synthesized Pt/CeO2 catalyst for CO oxidation. Journal of Physical Chemistry B, 2003. 107(25): p. 6122-6130.
34. Yim, S.D., et al., Decomposition of urea into NH3 for the SCR process. Industrial & Engineering Chemistry Research, 2004. 43(16): p. 4856-4863.
35. Gabrielsson, P.L.T., Urea-SCR in automotive applications. Topics in Catalysis, 2004. 28(1-4): p. 177-184.
36. Forzatti, P., Present status and perspectives in de-NOx SCR catalysis. Applied Catalysis a-General, 2001. 222(1-2): p. 221-236.
37. Koebel, M., G. Madia, and M. Elsener, Selective catalytic reduction of NO and NO2 at low temperatures. Catalysis Today, 2002. 73(3-4): p. 239-247.
38. Kwon, D.W., K.H. Park, and S.C. Hong, Enhancement of SCR activity and SO2 resistance on VOx/TiO2 catalyst by addition of molybdenum. Chemical Engineering Journal, 2016. 284: p. 315-324.
39. Lietti, L., I. Nova, and P. Forzatti, Selective catalytic reduction (SCR) of NO by NH3 over TiO2-supported V2O5-WO3 and V2O5-MoO3 catalysts. Topics in Catalysis, 2000. 11(1-4): p. 111-122.
40. Komatsu, T., et al., Kinetic-Studies of Reduction of Nitric-Oxide with Ammonia on Cu2+-Exchanged Zeolites. Journal of Catalysis, 1994. 148(2): p. 427-437.
41. Busca, G., et al., Chemical and mechanistic aspects of the selective catalytic reduction of NOx by ammonia over oxide catalysts: A review. Applied Catalysis B-Environmental, 1998. 18(1-2): p. 1-36.
42. Seo, C.K., et al., De-NOx characteristics of a combined system of LNT and SCR catalysts according to hydrothermal aging and sulfur poisoning. Catalysis Today, 2011. 164(1): p. 507-514.
43. Encyclopedia of automotive engineering. Choice: Current Reviews for Academic Libraries, 2015. 53(3): p. 397-397.
44. Bhalla, A.S., R.Y. Guo, and R. Roy, The perovskite structure - a review of its role in ceramic science and technology. Materials Research Innovations, 2000. 4(1): p. 3-26.
45. Weidenkaff, A., Preparation and application of nanostructured perovskite phases. Advanced Engineering Materials, 2004. 6(9): p. 709-714.
46. Tejuca, L.G. and J.L.G. Fierro, Properties and applications of perovskite-type oxides. Chemical industries. 1993, New York: M. Dekker. xi, 382 p.
47. Pena, M.A. and J.L. Fierro, Chemical structures and performance of perovskite oxides. Chem Rev, 2001. 101(7): p. 1981-2017.
48. Hewat, A.W., Cubic-Tetragonal-Orthorhombic-Rhombohedral Ferroelectric Transitions in Perovskite Potassium Niobate - Neutron Powder Profile Refinement of Structures. Journal of Physics C-Solid State Physics, 1973. 6(16): p. 2559-2572.
49. Kieslich, G., S.J. Sun, and A.K. Cheetham, Solid-state principles applied to organic-inorganic perovskites: new tricks for an old dog. Chemical Science, 2014. 5(12): p. 4712-4715.
50. Choi, S.O., et al., Experimental and Computational Investigation of Effect of Sr on NO Oxidation and Oxygen Exchange for La1–xSrxCoO3Perovskite Catalysts. ACS Catalysis, 2013. 3(12): p. 2719-2728.
51. Boukamp, B.A., The amazing Perovskite anode. Nature Materials, 2003. 2(5): p. 294-296.
52. Gandhi, H.S., G.W. Graham, and R.W. McCabe, Automotive exhaust catalysis. Journal of Catalysis, 2003. 216(1-2): p. 433-442.
53. Keav, S., et al., Structured Perovskite-Based Catalysts and Their Application as Three-Way Catalytic Converters-A Review. Catalysts, 2014. 4(3): p. 226-255.
54. Libby, W.F., Promising Catalyst for Auto Exhaust. Science, 1971. 171(3970): p. 499-&.
55. Voorhoeve, R.J., et al., Rare-earth oxides of manganese and cobalt rival platinum for the treatment of carbon monoxide in auto exhaust. Science, 1972. 177(4046): p. 353-4.
56. Voorhoeve, R.J., J.P. Remeika, and D.W. Johnson, Jr., Rare-Earth manganites: catalysts with low ammonia yield in the reduction of nitrogen oxides. Science, 1973. 180(4081): p. 62-4.
57. Voorhoeve, R.J., J.P. Remeika, and L.E. Trimble, Perovskites Containing Ruthenium as Catalysts for Nitric-Oxide Reduction. Materials Research Bulletin, 1974. 9(10): p. 1393-1404.
58. Voorhoeve, R.J., L.E. Trimble, and C.P. Khattak, Exploration of Perovskite-Like Catalysts - Ba2cowo6 and Ba2fenbo6 in No Reduction and Co Oxidation. Materials Research Bulletin, 1974. 9(5): p. 655-666.
59. Gallagher, P.K., D.W. Johnson, and F. Schrey, Studies of Some Supported Perovskite Oxidation Catalysts. Materials Research Bulletin, 1974. 9(10): p. 1345-1352.
60. Tanaka, H., An intelligent catalyst: the self-regenerative palladium-perovskite catalyst for automotive emissions control. Catalysis Surveys from Asia, 2005. 9(2): p. 63-74.
61. Tascon, J.M.D. and L.G. Tejuca, Catalytic Activity of Perovskite-Type Oxides Lameo3. Reaction Kinetics and Catalysis Letters, 1980. 15(2): p. 185-191.
62. Nitadori, T., T. Ichiki, and M. Misono, Catalytic Properties of Perovskite-Type Mixed Oxides (Abo3) Consisting of Rare-Earth and 3d Transition-Metals - the Roles of the a-Site and B-Site Ions. Bulletin of the Chemical Society of Japan, 1988. 61(3): p. 621-626.
63. Panich, N.M., et al., Oxidation of CO and hydrocarbons over perovskite-type complex oxides. Russian Chemical Bulletin, 1999. 48(4): p. 694-697.
64. Voorhoeve, R.J.H., et al., Perovskite-Like La1-Xkxmno3 and Related Compounds - Solid-State Chemistry and Catalysis of Reduction of No by Co and H2. Journal of Solid State Chemistry, 1975. 14(4): p. 395-406.
65. Hervieu, M., et al., Oxygen storage capacity and structural flexibility of LuFe2O4+x (0</=x</=0.5). Nat Mater, 2014. 13(1): p. 74-80.
66. Chang, Y.F. and J.G. McCarty, Novel oxygen storage components for advanced catalysts for emission control in natural gas fueled vehicles. Catalysis Today, 1996. 30(1-3): p. 163-170.
67. Tolpygo, V.K. and H. Viefhaus, Segregation at the Al(2)O(3)-FeCrAl interface during high-temperature oxidation. Oxidation of Metals, 1999. 52(1-2): p. 1-29.
68. Badini, C. and F. Laurella, Oxidation of FeCrAl alloy: influence of temperature and atmosphere on scale growth rate and mechanism. Surface & Coatings Technology, 2001. 135(2-3): p. 291-298.
69. Zhao, S., et al., A method to form well-adhered gamma-Al2O3 layers on FeCrAl metallic supports. Surface & Coatings Technology, 2003. 167(1): p. 97-105.
70. Ajami, E. and K.F. Aguey-Zinsou, Formation of OTS self-assembled monolayers at chemically treated titanium surfaces. Journal of Materials Science-Materials in Medicine, 2011. 22(8): p. 1813-1824.
71. Cosgrove, T., Colloid science : principles, methods and applications. 2005, Oxford, UK ; Ames, Iowa: Blackwell Pub. xvi, 288 p.
72. Zhang, H.M., Y. Teraoka, and N. Yamazoe, Preparation of Perovskite-Type Oxides with Large Surface-Area by Citrate Process. Chemistry Letters, 1987(4): p. 665-668.
73. Feng, C.H., et al., Ethanol sensing properties of LaCoxFe1-xO3 nanoparticles: Effects of calcination temperature, Co-doping, and carbon nanotube-treatment. Sensors and Actuators B-Chemical, 2011. 155(1): p. 232-238.
74. Mineshige, A., et al., Crystal structure and metal-insulator transition of La1-xSrxCoO3. Journal of Solid State Chemistry, 1996. 121(2): p. 423-429.
75. Suzuki, C., et al., The electronic structure of rare-earth oxides in the creation of the core hole. Chemical Physics, 2000. 253(1): p. 27-40.
76. Crumlin, E.J., et al., Surface strontium enrichment on highly active perovskites for oxygen electrocatalysis in solid oxide fuel cells. Energy & Environmental Science, 2012. 5(3): p. 6081-6088.
77. Matsumoto, Y., T. Sasaki, and J. Hombo, A New Preparation Method of Lacoo3 Perovskite Using Electrochemical Oxidation. Inorganic Chemistry, 1992. 31(5): p. 738-741.
78. Giraudon, J.M., A. Elhachimi, and G. Leclercq, Catalytic oxidation of chlorobenzene over Pd/perovskites. Applied Catalysis B-Environmental, 2008. 84(1-2): p. 251-261.
79. Niu, J.R., et al., Nanosized perovskite-type oxides La1-xSrxMO3-delta (M = CO, Mn; x=0, 0.4) for the catalytic removal of ethylacetate. Catalysis Today, 2007. 126(3-4): p. 420-429.
80. Prasad, D.H., et al., Synthesis of nano-crystalline La1-xSrxCoO3-delta perovskite oxides by EDTA-citrate complexing process and its catalytic activity for soot oxidation. Applied Catalysis a-General, 2012. 447: p. 100-106.
81. Meza, E., et al., Lithium-nickel cobalt oxides with spinel structure prepared at low temperature. XRD, XPS, and EIS measurements. Materials Letters, 2012. 70: p. 189-192.
82. Niu, J.R., et al., Preparation and characterization of highly active nanosized strontium-doped lanthanum cobaltate catalysts with high surface areas. Chinese Science Bulletin, 2006. 51(14): p. 1673-1681.
83. van der Heide, P.A.W., Systematic x-ray photoelectron spectroscopic study of La1-xSrx-based perovskite-type oxides. Surface and Interface Analysis, 2002. 33(5): p. 414-425.
84. Yoon, D.Y., et al., NO oxidation activity of Ag-doped perovskite catalysts. Journal of Catalysis, 2014. 319: p. 182-193.
85. Doi, Y., et al., ESR and IR studies of carbonate-containing hydroxyapatites. Calcif Tissue Int, 1982. 34(2): p. 178-81.
86. Say, Z., et al., Palladium doped perovskite-based NO oxidation catalysts: The role of Pd and B-sites for NOx adsorption behavior via in-situ spectroscopy. Applied Catalysis B-Environmental, 2014. 154: p. 51-61.
87. Li, X.G., et al., De-NOx in alternative lean/rich atmospheres on La1-xSrxCoO3 perovskites. Energy & Environmental Science, 2011. 4(9): p. 3351-3354.
88. Berthome, G., et al., Temperature dependence of metastable alumina formation during thermal oxidation of FeCrAl foils. Materials and Corrosion-Werkstoffe Und Korrosion, 2005. 56(6): p. 389-392.
89. Wu, X.D., et al., Influence of an aluminized intermediate layer on the adhesion of a gamma-Al2O3 washcoat on FeCrAl. Surface & Coatings Technology, 2005. 190(2-3): p. 434-439.
90. Choi, J.Y., T.L. Alford, and C.B. Honsberg, Solvent-controlled spin-coating method for large-scale area deposition of two-dimensional silica nanosphere assembled layers. Langmuir, 2014. 30(20): p. 5732-8.
91. Steiner, T., The hydrogen bond in the solid state. Angew Chem Int Ed Engl, 2002. 41(1): p. 49-76.
92. He, Y.H., X. Liang, and B.H. Chen, Globin-like mesoporous CeO2: A CO-assisted synthesis based on carbonate hydroxide precursors and its applications in low temperature CO oxidation. Nano Research, 2015. 8(4): p. 1269-1278.
93. Rahman, I.A., et al., Effect of the drying techniques on the morphology of silica nanoparticles synthesized via sol-gel process. Ceramics International, 2008. 34(8): p. 2059-2066.
94. Gonzalez-Velasco, J.R., et al., Thermal aging of Pd/Pt/Rh automotive catalysts under a cycled oxidizing-reducing environment. Catalysis Today, 2000. 59(3-4): p. 395-402.