Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/25627
標題: 摻氮比例及鍛燒溫度對於氮摻雜二氧化鈦之特性分析及其光催化反應動力模式探討
The Effect of N/Ti Molar Ratio and Calcination Temperature on the Characteristics of N-Doped TiO2 Catalyst and Kinetics of Heterogeneous Photocatalytic Oxidation of Ethylene
作者: 許惠然
Hsu, Hui-Jan
關鍵字: 摻氮二氧化鈦;N-doped TiO2;溶膠凝膠;摻氮比例;鍛燒溫度;乙烯可見光光催化;sol-gel method;doped nitrogen molar ratios;calcinations temperature;visible light photocatalytic of ethylene
出版社: 土壤環境科學系所
引用: Asahi, R., T. Morikawa, et al. (2001). "Visible-light photocatalysis in nitrogen-doped titanium oxides." Science 293(5528): 269-271. Aziz, A. A., K. S. Yong, et al. (2012). "Enhanced magnetic separation and photocatalytic activity of nitrogen doped titania photocatalyst supported on strontium ferrite." Journal of Hazardous Materials 199–200(0): 143-150. Bosc, F., A. Ayral, et al. (2003). "A simple route for low-temperature synthesis of mesoporous and nanocrystalline Anatase Thin Films." Chemistry of Materials 15(12): 2463-2468. Boulamanti, A. K. and C. J. Philippopoulos (2008). "Photocatalytic degradation of methyl tert-butyl ether in the gas-phase: A kinetic study." Journal of Hazardous Materials 160(1): 83-87. Boulamanti, A. K. and C. J. Philippopoulos (2009). "Photocatalytic degradation of C-5-C-7 alkanes in the gas-phase." Atmospheric Environment 43(20): 3168-3174. Bu, X. Z., G. K. Zhang, et al. (2010). "Preparation and photocatalytic properties of visible light responsive N-doped TiO2/rectorite composites." Microporous and Mesoporous Materials 136(1-3): 132-137. Bubacz, K., J. Choina, et al. (2010). "Studies on nitrogen modified TiO2 photocatalyst prepared in different conditions." Materials Research Bulletin 45(9): 1085-1091. Burda, C., Y. Lou, et al. (2003). "Enhanced nitrogen doping in TiO2 nanoparticles." Nano Letters 3(8): 1049. Cantau, C., T. Pigot, et al. (2010). "N-doped TiO2 by low temperature synthesis: Stability, photo-reactivity and singlet oxygen formation in the visible range." Journal of Photochemistry and Photobiology A: Chemistry 216(2-3): 201-208. Chang, C.-P., J.-N. Chen, et al. (2005). "Photocatalytic oxidation of gaseous DMF using thin film TiO2 photocatalyst." Chemosphere 58(8): 1071-1078. Cheng, X., X. Yu, et al. (2012). "Enhanced photocatalytic activity of nitrogen doped TiO2 anatase nano-particle under simulated sunlight irradiation." Energy Procedia 16, Part A(0): 598-605. Cong, Y., J. Zhang, et al. (2007). "Synthesis and characterization of nitrogen-doped TiO2 nanophotocatalyst with high visible light activity." The Journal of Physical Chemistry C 111(19): 6976-6982. Falconer, J. L. and K. A. Magrini-Bair (1998). "Photocatalytic and thermal catalytic oxidation of acetaldehyde on Pt/TiO2." Journal Of Catalysis 179(1): 171-178. Fu, X., L. A. Clark, et al. (1996). "Effects of reaction temperature and water vapor content on the heterogeneous photocatalytic oxidation of ethylene." Journal of Photochemistry and Photobiology A: Chemistry 97(3): 181-186. Gaya, U. I. and A. H. Abdullah (2008). "Heterogeneous photocatalytic degradation of organic contaminants over titanium dioxide: a review of fundamentals, progress and problems." Journal of Photochemistry and Photobiology C: Photochemistry Reviews 9(1): 1-12. Gu, D. E., Y. Lu, et al. (2008). "Facile preparation of micro-mesoporous carbon-doped TiO2 photocatalysts with anatase crystalline walls under template-free condition." Chemical Communications(21): 2453-2455. Guo, Y., X. W. Zhang, et al. (2007). "Structure and properties of nitrogen-doped titanium dioxide thin films grown by atmospheric pressure chemical vapor deposition." Thin Solid Films 515: 7117-7121. Hou, Y., H. Zheng, et al. (2011). "Effects of sintering temperature on physicochemical properties and photocatalytic activity of titanate nanotubes modified with sulfuric acid." Powder Technology 214(3): 451-457. Huang, D.-G., S.-J. Liao, et al. (2006). "Preparation of visible-light responsive N-F-codoped TiO2 photocatalyst by a sol-gel-solvothermal method." Journal of Photochemistry and Photobiology A: Chemistry 184(3): 282-288. Huang, D., S. Liao, et al. (2008). "Synthesis and characterization of visible light responsive N-TiO2 mixed crystal by a modified hydrothermal process." Journal of Non-Crystalline Solids 354(33): 3965-3972. Huang, Y., W. K. Ho, et al. (2008). "Effect of carbon doping on the mesoporous structure of nanocrystalline titanium dioxide and its solar-light-driven photocatalytic degradation of NOx." Langmuir 24(7): 3510-3516. Hussain, M., N. Russo, et al. (2011). "Photocatalytic abatement of VOCs by novel optimized TiO2 nanoparticles." Chemical Engineering Journal 166(1): 138-149. Ihara, T., M. Miyoshi, et al. (2003). "Visible-light-active titanium oxide photocatalyst realized by an oxygen-deficient structure and by nitrogen doping." Applied Catalysis B: Environmental 42(4): 403-409. Irie, H., Y. Watanabe, et al. (2003). "Nitrogen-concentration dependence on photocatalytic activity of TiO2-xNx powders." Journal of Physical Chemistry B 107(23): 5483-5486. Jang, J. S., H. G. Kim, et al. (2006). "Formation of crystalline TiO2−xNx and its photocatalytic activity." Journal of Solid State Chemistry 179(4): 1067-1075. Janitabar-Darzi, S., A. R. Mahjoub, et al. (2009). "Investigation of structural, optical and photocatalytic properties of mesoporous TiO2 thin film synthesized by sol–gel templating technique." Physica E: Low-dimensional Systems and Nanostructures 42(2): 176-181. Jo, W. K. and J. T. Kim (2009). "Application of visible-light photocatalysis with nitrogen-doped or unmodified titanium dioxide for control of indoor-level volatile organic compounds." Journal of Hazardous Materials 164(1): 360-366. Kim, S. B. and S. C. Hong (2002). "Kinetic study for photocatalytic degradation of volatile organic compounds in air using thin film TiO2 photocatalyst." Applied Catalysis B: Environmental 35(4): 305-315. Kobayakawa, K., Y. Murakami, et al. (2005). "Visible-light active N-doped TiO2 prepared by heating of titanium hydroxide and urea." Journal of Photochemistry and Photobiology A: Chemistry 170(2): 177-179. Kosowska, B., S. Mozia, et al. (2005). "The preparation of TiO2-nitrogen doped by calcination of TiO2‧xH2O under ammonia atmosphere for visible light photocatalysis." Solar Energy Materials and Solar Cells 88(3): 269-280. Ku, Y., C. M. Ma, et al. (2001). "Decomposition of gaseous trichloroethylene in a photoreactor with TiO2-coated nonwoven fiber textile." Applied Catalysis B-Environmental 34(3): 181-190. Kun, R., M. Szekeres, et al. (2006). "Photooxidation of dichloroacetic acid controlled by pH-stat technique using TiO2/layer silicate nanocomposites." Applied Catalysis B: Environmental 68(1–2): 49-58. Kun, R., S. Tarjan, et al. (2009). "Preparation and characterization of mesoporous N-doped and sulfuric acid treated anatase TiO2 catalysts and their photocatalytic activity under UV and Vis illumination." Journal of Solid State Chemistry 182(11): 3076-3084. Kuo, Y.-L., T.-L. Su, et al. (2011). "A study of parameter setting and characterization of visible-light driven nitrogen-modified commercial TiO2 photocatalysts." Journal of Hazardous Materials 190(1–3): 938-944. Lee, S., I.-S. Cho, et al. (2010). "Influence of nitrogen chemical states on photocatalytic activities of nitrogen-doped TiO2 nanoparticles under visible light." Journal of Photochemistry and Photobiology A: Chemistry 213(2-3): 129-135. Li, D., H. Haneda, et al. (2005). "Visible-light-driven nitrogen-doped TiO2 photocatalysts: effect of nitrogen precursors on their photocatalysis for decomposition of gas-phase organic pollutants." Materials Science and Engineering B 117: 67-75. Li, F. B. and X. Z. Li (2002). "The enhancement of photodegradation efficiency using Pt-TiO2 catalyst." Chemosphere 48(10): 1103-1111. Li, Y., D.-S. Hwang, et al. (2005). "Synthesis and characterization of carbon-doped titania as an artificial solar light sensitive photocatalyst." Chemical Physics Letters 404(1-3): 25-29. Li, Y. X., Y. A. Jiang, et al. (2010). "Nitrogen-doped TiO2 modified with NH4F for efficient photocatalytic degradation of formaldehyde under blue light-emitting diodes." Journal of Hazardous Materials 182(1-3): 90-96. Lindgren, T., J. M. Mwabora, et al. (2003). "Photoelectrochemical and optical properties of nitrogen doped titanium dioxide films prepared by reactive DC magnetron sputtering." The Journal of Physical Chemistry B 107(24): 5709-5716. Linsebigler, A. L., G. Lu, et al. (1995). "Photocatalysis on TiO2 surfaces: principles, mechanisms, and selected results." Chemical Reviews 95(3): 735-758. Ma, Y., J. Zhang, et al. (2010). "Synthesis and characterization of thermally stable Sm,N co-doped TiO2 with highly visible light activity." Journal of Hazardous Materials 182(1–3): 386-393. Mekprasart, W. and W. Pecharapa (2011). "Synthesis and characterization of nNitrogen-doped TiO2 and its photocatalytic activity enhancement under visible light." Energy Procedia 9(0): 509-514. Obee, T. N. and R. T. Brown (1995). "TiO2 photocatalysis for indoor air applications: effects of humidity and trace contaminant levels on the oxidation rates of formaldehyde, toluene, and 1,3-butadiene." Environmental Science & Technology 29(5): 1223-1231. Obee, T. N. and S. O. Hay (1997). "Effects of moisture and temperature on the photooxidation of ethylene on Titania." Environmental Science and Technology 31(7): 2034-2038. Pap, Z., L. Baia, et al. (2012). "Correlating the visible light photoactivity of N-doped TiO2 with brookite particle size and bridged-nitro surface species." Catalysis Communications 17(0): 1-7. Parida, K. M. and B. Naik (2009). "Synthesis of mesoporous TiO2-xNx spheres by template free homogeneous co-precipitation method and their photo-catalytic activity under visible light illumination." Journal of Colloid and Interface Science 333(1): 269-276. Peng, Y.-P., E. Yassitepe, et al. (2012). "Photoelectrochemical Degradation of Azo Dye over Pulsed Laser Deposited Nitrogen-doped TiO2 Thin Film." Applied Catalysis B: Environmental(0).1-34. Pomoni, K., A. Vomvas, et al. (2008). "Electrical conductivity and photoconductivity studies of TiO2 sol-gel thin films and the effect of N-doping." Journal of Non-Crystalline Solids 354(35-39): 4448-4475. Ranjit, K. T. and B. Viswanathan (1997). "Synthesis, characterization and photocatalytic properties of iron-doped TiO2 catalysts." Journal of Photochemistry and Photobiology A: Chemistry 108(1): 79-84. Sato, S. (1986). "Photocatalytic activity of NOx-doped TiO2 in the visible light region." Chemical Physics Letters 123(1-2): 126-128. Shaban, Y. A. and S. U. M. Khan (2009). "Carbon modified (CM)-n-TiO2 thin films for efficient water splitting to H-2 and O-2 under xenon lamp light and natural sunlight illuminations." Journal of Solid State Electrochemistry 13(7): 1025-1036. Shen, M., Z. Y. Wu, et al. (2006). "Carbon-doped anatase TiO2 obtained from TiC for photocatalysis under visible light irradiation." Materials Letters 60(5): 693-697. Shen, X.-Z., J. Guo, et al. (2008). "Visible-light-driven titania photocatalyst co-doped with nitrogen and ferrum." Applied Surface Science 254(15): 4726-4731. Shen, X.-Z., Z.-C. h. Liu, et al. (2009). "Degradation of nitrobenzene using titania photocatalyst co-doped with nitrogen and cerium under visible light illumination." Journal of Hazardous Materials 162: 1193-1198. Shi, J., S. Chen, et al. (2012). "Sol-gel preparation and visible light photocatalytic activity of nitrogen doped titania." Procedia Engineering 27(0): 564-569. Sreethawong, T., S. Laehsalee, et al. (2008). "Comparative investigation of mesoporous- and non-mesoporous-assembled TiO2 nanocrystals for photocatalytic H2 production over N-doped TiO2 under visible light irradiation." International Journal of Hydrogen Energy 33(21): 5947-5957. Sun, H., S. Wang, et al. (2010). "Halogen element modified titanium dioxide for visible light photocatalysis." Chemical Engineering Journal 162(2): 437-447. Sun, H. Q., Y. Bai, et al. (2009). "Photocatalytic decomposition of 4-chlorophenol over an efficient N-doped TiO2 under sunlight irradiation." Journal Of Photochemistry And Photobiology A-Chemistry 201(1): 15-22. Tachikawa, T., S. Tojo, et al. (2004). "Photocatalytic Oxidation Reactivity of Holes in the Sulfur- and Carbon-Doped TiO2 Powders Studied by Time-Resolved Diffuse Reflectance Spectroscopy." The Journal of Physical Chemistry B 108(50): 19299-19306. Tryba, B. (2008). "Immobilization of TiO2 and Fe-C-TiO2 photocatalysts on the cotton material for application in a flow photocatalytic reactor for decomposition of phenol in water." Journal of Hazardous Materials 151(2-3): 623-627. Ulrike, D. (2003). "The surface science of titanium dioxide." Surface Science Reports 48(5–8): 53-229. Vorontsov, A. V., E. N. Kurkin, et al. (1999). "Study of TiO2 deactivation during gaseous acetone photocatalytic oxidation." Journal of Catalysis 186(2): 318-324. Vorontsov, A. V., E. N. Savinov, et al. (1997). "Quantitative studies on the heterogeneous gas-phase photooxidation of CO and simple VOCs by air over TiO2." Catalysis Today 39(3): 207-218. Wang, H. Q., Z. M. Zhang, et al. (2008). "A novel one-step photocatalytic synthesis of benzo[d]oxazol-2(3H)-one with C-doped TiO2 nanoparticle." Chemistry Letters 37(11): 1156-1157. Wang, J., Z. Wang, et al. (2010). "Visible light-driven nitrogen doped TiO2 nanoarray films: Preparation and photocatalytic activity." Journal of Alloys and Compounds 494(1–2): 372-377. Wang, K. H., H. H. Tsai, et al. (1998). "The kinetics of photocatalytic degradation of trichloroethylene in gas phase over TiO2 supported on glass bead." Applied Catalysis B-Environmental 17(4): 313-320. Wang, K. H., H. H. Tsai, et al. (1998). "A study of photocatalytic degradation of trichloroethylene in vapor phase on TiO2 photocatalyst." Chemosphere 36(13): 2763-2773. Wang, S. H., T. K. Chen, et al. (2007). "Nanocolumnar titania thin films uniquely incorporated with carbon for visible light photocatalysis." Applied Catalysis B-Environmental 76(3-4): 328-334. Wang, Y., C. Feng, et al. (2010). "Enhanced visible light photocatalytic activity of N-doped TiO2 in relation to single-electron-trapped oxygen vacancy and doped-nitrogen." Applied Catalysis B: Environmental 100(1-2): 84-90. Wong, M. S., H. P. Chou, et al. (2006). "Reactively sputtered N-doped titanium oxide films as visible-light photocatalyst." Thin Solid Films 494(1-2): 244-249. Wu, D. Y., M. C. Long, et al. (2010). "Low temperature hydrothermal synthesis of N-doped TiO2 photocatalyst with high visible-light activity." Journal of Alloys and Compounds 502(2): 289-294. Wu, Z., F. Dong, et al. (2008). "Visible light induced electron transfer process over nitrogen doped TiO2 nanocrystals prepared by oxidation of titanium nitride." Journal of Hazardous Materials 157: 57-63. Xing, M., J. Zhang, et al. (2009). "New approaches to prepare nitrogen-doped TiO2 photocatalysts and study on their photocatalytic activities in visible light." Applied Catalysis B: Environmental 89(3-4): 563-569. Xu, J.-h., W.-L. Dai, et al. (2008). "Simple fabrication of thermally stable apertured N-doped TiO2 microtubes as a highly efficient photocatalyst under visible light irradiation." Catalysis Communications 9(1): 146-152. Xu, J., Y. Ao, et al. (2008). "A simple route for the preparation of Eu, N-codoped TiO2 nanoparticles with enhanced visible light-induced photocatalytic activity." Journal of Colloid and Interface Science 328: 447-451. Xu, J. P., Y. B. Lin, et al. (2006). "Enhanced ferromagnetism in Mn-doped TiO2 films during the structural phase transition." Solid State Communications 140(11-12): 514-518. Yamashita, H., M. Honda, et al. (1998). "Preparation of titanium oxide photocatalysts anchored on porous silica glass by a metal ion-implantation method and their photocatalytic reactivities for the degradation of 2-propanol diluted in water." The Journal of Physical Chemistry B 102(52): 10707-10711. Yamashita, H., Y. Ichihashi, et al. (1999). "Characterization of metal ion-implanted titanium oxide photocatalysts operating under visible light irradiation." Journal of Synchrotron Radiation 6(3): 451-452. Yamazaki, S., S. Tanaka, et al. (1999). "Kinetic studies of oxidation of ethylene over a TiO2 photocatalyst." Journal of Photochemistry and Photobiology A-Chemistry 121(1): 55-61. Yang, M.-C., T.-S. Yang, et al. (2004). "Nitrogen-doped titanium oxide films as visible light photocatalyst by vapor deposition." Thin Solid Films 469-470: 1-5. Yang , T.-S., M.-C. Yang, et al. (2006). "Effect of N2 ion flux on the photocatalysis of nitrogen-doped titanium oxide films by electron-beam evaporation." Applied Surface Science 252: 3729–3736. Yu, J., M. Zhou, et al. (2006). "Preparation, characterization and photocatalytic activity of in situ N,S-codoped TiO2 powders." Journal of Molecular Catalysis A: Chemical 246(1–2): 176-184. Zhang, Z., X. Wang, et al. (2010). "Nitrogen-doped titanium dioxide visible light photocatalyst: Spectroscopic identification of photoactive centers." Journal of Catalysis 276(2): 201-214. Zhao, X. F., X. F. Meng, et al. (2004). "Preparation and photocatalytic activity of Pb-doped TiO2 thin films." Journal of Inorganic Materials 19(1): 140-146. Zhou, X., F. Peng, et al. (2011). "Preparation of nitrogen doped TiO2 photocatalyst by oxidation of titanium nitride with H2O2." Materials Research Bulletin 46(6): 840-844. 王勝民 (2000). 化工資訊月刊 8: 35. 高濂、鄭珊、張青紅 ( 2004). "奈米光觸媒." 初版,五南圖書出版股份有限公司. 張碩修 (2008). "具可見光吸收之銅、鉻、鐵改質型TiO2 奈米光觸媒." 東海大學環境科學與工程系研究所碩士論文. 陳永芳 (2003). "以四異丙醇鈦為前驅物利用化學氣相沉積法和水解法製備二氧化鈦." 國立交通大學應用化學所博士論文. 游智宏 (2005). "可見光二氧化鈦奈米管製備、改質及光觸媒性質之研究." 中原大學化學工程學系碩士論文. 藤鳴昭 (2000). "酸化光觸媒的世界." 工業材料 48: 17.
摘要: 
蔬果保存期限受限於催化蔬果成熟之植物荷爾蒙乙烯。因此,藉由摻氮改質之二氧化鈦光觸媒能於一般可見光應答降解乙烯污染物反應,使之移除蔬果本身所產出荷爾蒙乙烯,進而能使蔬果之保鮮期增長,將為此宗旨。鑒此,本研究選用四異丙氧基鈦為鈦源,氨水為氮源,以溶膠凝膠法製備氮摻雜二氧化鈦光觸媒,探討合成過程之鍛燒溫度及氮源與鈦源莫耳比例對氮摻雜二氧化鈦之材料特性影響,以建立最佳合成參數,並進行以乙烯氣體為目標污染物之可見光光催化反應試驗。
研究結果顯示,批次可見光光催化反應降解乙烯,發現本研究最理想之氮摻雜二氧化鈦光觸媒材料為鍛燒溫度400℃,摻氮比例2.0莫耳比。因此,材料特性影響之實驗結果顯示,針對最佳鍛燒溫度為400℃,摻氮比例2.0莫耳比進行探討。熱量重量損失之結果發現二氧化鈦銳鈦礦相轉變成金紅石相溫度有遲緩之現象,符合晶相結構分析之結果。晶相結構得知最佳摻氮光觸媒材料有較小之結晶尺寸約為28 nm,其尺寸相近高解析穿透式電子顯微鏡之最小奈米結晶尺寸約為11 ± 1 nm。比表面積及孔徑分佈方面顯示等溫吸脫附曲線在400℃為類型IV,而遲滯環為類型H3,此顯示於摻氮條件可形成良好之介孔洞結構;觸媒也顯示有較大之比表面積與孔洞體積,分別為98m2/g與0.26 cm3/g,而相對孔洞尺寸分佈曲線與孔洞尺寸可得知有較小之孔洞尺寸約為65 nm。粒徑尺寸呈現稍不規則之變化,但大致趨勢可發現較低溫度與較高摻氮比例有較小之粒徑尺寸。選區繞射 (SAED) 發現鍛燒溫度於400℃時,有良好之銳鈦礦相之繞射環,其平面晶相d-sapcing 約為0.35 nm,符合晶相結構鍛燒低溫結果。紫外光-可見光吸收光譜之波長範圍於400 – 550 nm,有較佳可見光吸收值之現象。X射線光電子能譜之N 1s可發現於399 - 400 eV範圍內有波峰鍵結能,皆屬於間位氮 (Interstitial N) (Ti-O-N) 鍵結之範圍,此為氮原子鍵結於氧原子所產生之化學鍵結。表面官能基看到於光催化反應前只有O-H團吸附於觸媒表面,而經過光催化反應後,其觸媒表面有更多之O-H團及水分子吸附於觸媒表面。元素分析因受限於儀器分析背景訊號,而有較不規則之變化,但大致趨勢以較低溫度與較高摻氮比例有較多之氮含量摻雜進入二氧化鈦。
可見光光催化降解乙烯試驗中,影響光催化環境控制因子可分為氣體流速、乙烯初始濃度、水氣濃度、氧氣濃度、光強度及反應溫度等六大影響因子。氣體流速方面,氣體流速 < 1000 mL/min,受限於質傳控制;氣體流速 > 1000 mL/min,受限於表面反應控制。乙烯初始濃度方面,乙烯初始濃度 < 500 ppmv,活性位置尚未佔滿,乙烯初始濃度 > 500 ppmv,活性位置則已填滿,未能再增加乙烯降解速率。水氣濃度方面,水氣濃度 < 1561 ppmv,有更多氫氧自由基進行光催化反應;水氣濃度 > 1561 ppmv且 < 6239 ppmv,水分子與乙烯分子競爭而減少活性位置,歸因同類型於光觸媒表面;當水氣濃度 > 6239 ppmv,活性位置則已填滿,不會再降低乙烯降解速率。氧氣濃度方面,氧氣濃度 < 50000 ppmv,有更多超氧自由基進行光催化反應;氧氣濃度 > 50000 ppmv,其光催化所需氧氣分子含量已足夠,更多氧分子含量未能進一步增加降解速率,與乙烯分子屬於不同類型於光觸媒表面,因此也不會抑制光催化乙烯降解速率。可見光強度方面,隨光強度增加有更多之光源能量使電子電洞對受光能量激發而分離,且減少電子電洞對再結合作用,達到增加光催化降解乙烯速率,本實驗之可見光源效能約為0.49。反應溫度方面,較低反應溫度能使水氣置換TiO2表面吸附的乙烯分子,因此水氣會抑制乙烯的反應效率;較高反應溫度則使水分子親和性降低,致水分子蒸發或熱脫附,表面釋出大量活性位址,促進乙烯催化之反應速率。

The conservation deadline of vegetables and fruits are limiting with plants hormone ethylene which always are promoting them ripe. Therefore, we use the photocatalyst of N-doped TiO2 degrade ethylene pollutant under visible light response. It aims that we can remove of ethylene for vegetables and fruits, improving the conservation deadline of vegetables and fruits. In our studies, the titanium tetraisopropoxide and aqua ammonia are titanium and nitrogen precursor, respectively. We had focused on the sol gel synthesis of N-doped TiO2 at calcination temperatures and various Aqua ammonia/TTIP molar ratios for photocatalyst of N-doped TiO2 characterized effect, in order to establish optimum synthesis parameter. Eventually, N-doped TiO2 were evaluated photocatalytic activity for the decomposition of the ethylene target pollutant under the visible light irradiation.
The research result indicates that the optimum synthesis condition is calcinations temperature 400℃ and ammonia/TTIP 2.0 molar ratio for photocatalyst of N-doped TiO2. Hence, we focused on calcinations temperature 400℃ and ammonia/TTIP 2.0 molar ratio to discuss. On the part of caloricity and gravity loss, it retards the phase of titanium dioxide transformation from anatase to rutile, consistency with crystal structure results. Respecting crystal structure, we can find that the optimium N-doped TiO2 photocatalyst possesses the smaller crystalline sizes about 28 nm, to approach with the nanocrystalline size about 11 ± 1 nm for crystal morphology results. In the way of BET, the adsorption-desorption isotherm curve of photocatalysts of N-doped TiO2 calcination at 400℃ belong to type IV, and the hysteresis loops displays H3, that is formation the good mesopores structure with the nitrogen doped into lattice of titanium dioxide. It exhibits the large specific surface areas and pore volumes for 98 m2/g and 0.26 cm3/g, respectively. It also presents the smaller pore sizes about 65 nm. Particle sizes reveal that the irregular change, but it discovers the smaller particle sizes with the lower temperature and higher nitrogen doped molar ratios. For selection area election diffraction, it’s the good phase of anantase of titanium dioxide diffusion rings calcinations at 400℃, and the interplaner d-spacing is about 0.35 nm for phase of anatase, consistent with the crystal structure results. The absorption wavelength between 400 - 550 nm for UV-visible displays excellent visible light range absorption. The x-ray photoelectron spectroscopy of N 1s bind energy range between 399 – 400 eV exhibit the peak which belong the interstitial N, namely the nitrogen atoms bond after the oxygen atoms. On the part of surface fundation analysis, the N-doped TiO2 photocatalyst presents the O-H groups adsorption on the photocatalyst surface before the photocatalytic reaction, however the more ones after the photocatalytic reaction. For element analysis, the N-doped TiO2 photocatalyst reveals irregular change due to the bad instrument analysis signal, notwithstanding it discovers the smaller particle sizes with the lower temperature and higher nitrogen doped molar ratios.
There are six environmental effect factors inclunding flow rate, ethylene initial concentration, water concentration, oxygen concentration, light intensity and reaction temperature for photocatalytic reaction test decomposes ethylene under the visible light irradiation. Respecting of flow rate smaller than 1000 mL/min, it exposes limiting due to the mass flow control; the flow rate larger than 1000 mL/min, it shows limiting owing to the surface reaction control. On the part of ethylene initial concentration smaller than 500 ppmv, the activity sites of photocatalyst is unoccupied fully; the ethylene initial concentration larger than 500 ppmv, the activity sites of photocatalyst is occupied fully, cannot increasing the ethylene degrade rate. In the way of water concentration smaller than 1561 ppmv, it processes photocatalytic reaction with the much hydroxyl radical; the water concentration larger than 1561 ppmv and smaller than 6239 ppmv, it reduces the activity sites of photocatalyst because of water molecular competition with ethylene molecular owing to the same type of photocatalyst surface activity sites; the water concentration larger than 6239 ppmv, the activity sites of photocatalyst has been occupied fully, did not decreasing the ethylene degrade rate. Respecting of oxygen concentration smaller than 50000 ppmv, it operates photocatalytic reaction with the much superoxide radical; the oxygen concentration larger than 50000 ppmv, the oxygen molecular is much enough and can not improve the ethylene decomposition rate with increasing the oxygen concentration. Moreover, oxygen molecular cannot competition with ethylene molecular due to the different type of photocatalyst surface activity sites. On the part of light intensity, there are much light source energy can let the electron-hole pairs dispersion with increasing the light source intensity, and reducing the recombination of electron-hole pairs, promoting the ethylene decomposition rate. In our research, the light intensity efficient is about 0.49. In the way of reaction temperature, water molecular can substitute the ethylene molecular on titanium dioxide surface with low reaction temperature. Hence, the water concentration inhibited ethylene degrade rate; water molecular reduces the hydrophilic ability with high reaction temperature, leading water vapor or desorption and releasing a large number of activity sites of photocatalyst. Therefore, It can improve ethylene degrade rate.
URI: http://hdl.handle.net/11455/25627
其他識別: U0005-0108201211565600
Appears in Collections:土壤環境科學系

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