摘要
由于汽车尾气造成的环境污染日益严重同时排放法规日益严格,要求开发氧传感器结合三元催化系统来检测控制汽车尾气的排放,使其达到相关的排放标准。
研究了烧结助剂Li2O对Ce0.8Gd0.2O1.9性能的影响,制备了YST/CGO双相复合及LSC混合导体(Mixed Conductor-MIC)材料,在此基础上制备了共压及厚膜型致密扩散层极限电流氧传感器。借助X射线衍射(XRD)、扫描电镜(SEM)、交流阻抗谱(EIS)等手段对材料致密度、物相结构、微观形貌和导电性能进行了研究。应用SEM分析了传感器的微观结构,采用电位扫描测试分析了氧浓度与极限电流的关系。
添加3mol%Li后,1450℃烧结试样相对密度与1600℃烧结的Ce0.8Gd0.2O1.9相当,使烧结温度降低150℃。1450℃3mol%Li掺杂的烧结试样的平均晶粒尺寸为5μm且为萤石结构单相,在800℃具有最高电导率水平达到100(S.cm),活化能最小仅为0.77eV。
YST/CGO试样在1600℃烧结的体密度均在90 %以上。YST/CGO1与YST/CGO2的两相颜色差异明显,晶粒完整,晶型清晰。烧结试样中的各组分仍保持本身单相结构并未发生相反应。试样的电导率随YST比例增大呈下降趋势,YST比例的增大未使电导率增大。其中YST/CGO1的电导率最大约为10-1(S.cm),活化能为1.01eV。
以YST/CGO1与YST/CGO2作扩散层制备的氧传感器在氧浓度低于1000ppm,温度范围在600~700℃内,电压为0.5~1.1V范围内出现较理想的极限电流平台,在氧浓度范围为300~1000ppm范围内极限电流随着氧浓度的增加而增加,且具有良好的线性关系,相关系数都在0.99以上。
以LSC做致密扩散层制备的厚膜型氧传感器的膜层厚度约为30μm左右,与固体电解质结合良好界面清晰。在650~800℃,氧浓度在7000~105000ppm之间,电压范围为0.2V~1.0V出现极限电流平台。极限电流与氧浓度呈很好线性关系。
Exhaust pollution from automobile is becoming worse and worse, while laws and regulations to control exhaust pollution are becoming more and more strict. Scientists research an oxygen sensor which controls and monitors the phenomenon of discharging poisonous gas by combining with 3-way catalysis system. Limiting current oxygen sensor receives much attention lately as it has fast response and high sensitive characteristics, and does not need any reference gas.
Effect of Li2O additive on phase structure, density and electric properties of Ce0.8Gd0.2O1.9 were investigated, YST / CGO dual-phase composite Mixed Conductor (MIC) dense diffusion layer materials were prepared. Limiting current oxygen sensor using YSZ and CGO as electrolyte and LSC and YST / CGO as dense diffusion barrier were constructed by screen printing technique and co-pressing and co-sintering, respectively. The crystalline phase, microstructure and electrical conductivity of materials were investigated by XRD, SEM and EIS, respectively. Sensor’s microstructures were analyzed by SEM. The relations between voltage and oxygen concentration of limiting current were investigated by dynamic scan.
When doped with 3 mol% Li, the bulk density of CGO sintered at 1450℃was the same as that of pure CGO sintered at 1600℃, the sintering temperature reduced by150℃from 1600℃without aids. After adding 3 mol% Li, the major phase of the sample was fluorite structure for single-phase CGO when sintering at 1450℃, the average grain size was about 5μm , the electrical conductivity reached 100 (S.cm) at 800℃with the highest level, the activation energy was only 0.77eV.
The bulk density of YST / CGO samples sintered at 1600℃was more than 90%. The two-phase of YST/CGO1 and YST/CGO2 had an obvious difference in color, the grain was clear. Sintered sample of each component was still single-phase structure for none reaction occurred. The electrical conductivity of the sample decreased with the proportion of YST increased. YST/CGO1 had the maximal electrical conductivity about 10-1 (S.cm), the activation energy was 1.01eV.
The oxygen sensors, with YST/CGO1 and YST/CGO2 as diffusion layers, respectively, both got stable current plateaus in oxygen concentration from 300ppm to 800ppm when temperature was from 600~700℃and voltage was 0.5~1.1V. There was a excellent linear relationship between limiting current and oxygen concentration,and the correlation coefficient was above 0.99.
Thick film LSC as dense diffusion layer based limiting current oxygen sensors prepared by screen printing technology on YSZ solid electrolyte. SEM results indicated that the LSC film thickness was about 30μm. The limiting current increased almost linearly with increased oxygen concentration in the range of 7000~105000ppm under 650~800℃. The sensor displayed a good oxygen sensitive performance.
引文
[1]程晟.氧气传感器的工作原理及使用[J].汽车与配件,1999,40:15-16.
[2]李红卫,言卫平,李旭东.氧化锆氧传感器在汽车电喷系统中的应用[J].陶瓷工程,2000,34 (2):16-20.
[3]何锐,刘光葵,孙尧卿.氧传感器及其在汽车中的应用[J].传感器技术,1999,18(3):1-4.
[4]赵艳琴,王岭,朱靖.汽车用氧传感器的研究与进展[J].传感器世界,12(5):6-10
[5]王连红. ZrO2氧传感器的发展与应用[J].山东陶瓷,2004,27(2):15-18.
[6]曾昭茂,罗练谋.氧传感器在汽车排气净化中的作用[J].中南汽车运输,1999,1:15-18.
[7] XU Y. Platinum-titania oxygen sensors and their sensing mechanisms. [J]. Sensors and Actuators B, 1993, 13-14: 492-494
[8]藤迟英也.最新电控汽油喷射[M].林学东,译.北京:北京理工大学出版社,1998.
[9]马玉芳,卢世魁.汽车发动机用氧传感器的研究[J].工矿自动化,2003,5:19-20.
[10] SHARMA R.K, BHATNAGAR M.C. Improvement of the oxygen gas sensitivity in doped TiO2 thick films [J]. Sensors and Actuators B, 1999,56: 215-219.
[11] MASAHIRO K, SEIKOU S, TSUYOSHI F, et al. Limiting-current type Air/ Fuel ratio sensor using porous zirconia layer without inner gas chambers: proposal for a quick-startup sensor. Sensors and Actuators B ,2001, 73 :40 -48.
[12] SRIDHAR K.R, BLANCHARD J. A. Electronic conduction in low oxygen partial pressure measurements using an amperometric zirconia oxygen sensor. Sensors and Actuators B, 1 999, 59:60-67.
[13] AKIYOSHI A, HIDEOY, MITSUHIRO N ,et al. Limiting current type of oxygen sensor with high performance, Sensors and Actuators B, 1990, 11:312- 318
[14] SAJI K. Characteristics of limiting current-type oxygen sensor [J]. Journal of the Electrochemical Society, 1987, 134(10):2430-2435.
[15] RIEGEL J, NEUMANN H, WIEDENMANN H. Exhaust gas sensors for automotive emission control [J]. Solid State Ionics, 2002, 152-153:783-800
[16]李福燊,夏晖,杨媚,等.具有LSM致密扩散障碍层的片式极限电流型氧传感器[J].无机材料学报,2004,19(2):411-416.
[17]方国家.氧传感器的研究与进展[J].无机材料学报,1998,13(6):769-775
[18]杨媚.致密扩散层极限电流型氧传感器的研究[D].北京:北京科技大学,2004.
[19] FERNANDO G. Dense diffusion barrier limiting current oxygen sensors [J]. Sensors and Actuators B, 1998, 50: 125-130.
[20] KOHSEI I. Planar type of limiting current oxygen sensor [J]. Sensors and Actuators B, 1993,13: 41-44.
[21] TADASHI I, KEIICHI S. Low temperature operation of thin-film limiting-current type oxygen sensor using graded-composition layer electrodes [J]. Sensors and Actuators B, 2008, 129: 874-880.
[22]陶颖,王零森,陈振华. ZrO2陶瓷的离子导电性及其应用[J].中国陶瓷,1999,35(5):12-15
[23] GOODENOUGH J B. Oxide-ion electrolytes [J]. Annual Review of Materials Research, 2003, 33: 91-128.
[24] TULLER H, NOWICK A. Doped ceria as a solid oxide electrolyte [J]. Journal of Electrochemical Society, 1975, 122: 255-259.
[25] INABA H, TAGAWA H. Ceria-based solid electrolytes [J]. Solid State Ionics, 1996, 83: 1-16.
[26] MOGENSEN M, SAMMES N M. Physical, chemical and electrochemical properties of pure and doped ceria [J]. Solid State Ionics, 2000, 129: 63-94.
[27] MOGENSEN M, THOMAS LINDEGAARD. Physical properties of mixed conductor SOFC anodes of doped CeO2 [J]. Journal of Electrochemical Society, 1994, 141: 2122-2128.
[28] EGUCHI K. Ceramic materials containing rare earth oxides for solid oxide fuel cell [J]. Journal of Alloys and Compounds, 1997, 250: 486-491.
[29] PORAT O, HEREMANS C, TULLER H. L. Stability and mixed ionic electronic conduction in Gd2 (Ti1?xMox)2O7 under anodic conditions [J]. Solid State Ionics, 1997, 94:75-83.
[30] MCEVOY A. J. Thin SOFC electrolytes and their interfaces [J]. Solid State Ionics, 2000, 132: 159-165
[31] RIESS I. Mixed ionic-electronic conductors-material properties and applications [J]. Solid State Ionics, 2003, 157:1-17.
[32] SHAULA A, KHARTON V.V, MARQUES F, et al. Oxygen permeability of mixed-conducting composite membranes [J]. Journal of Solid State Electrochemistry, 2006, 10:28–40.
[33] HIDETO K, LIMING Y, CRAIG P, et al. Y-doped SrTiO3 based sulfur tolerant anode for solid oxide fuel cells [J]. Journal of Power Sources, 2007, 164: 510-518.
[34] SHAULA A. L, KHARTON V. V, MARQUES F. M, et al. Oxygen permeability of mixed-conducting composite membranes: effects of phase interaction [J]. Journal of Solid State Electrochemical, 2006, 10: 28-40.
[35]工藤澈一.固态离子学[M].董冶长,译.北京:北京工业大学出版社,1992.
[36] BARBUCCI A, BOZZO R, CERISOLA G, et al. Characterization of composite SOFC cathodes using electrochemical impedance spectroscopy. Analysis of Pt/YSZ and LSM/YSZ electrodes [J]. Electrochimica Acta, 2002, 47: 2183-2188.
[37] BARISON S, BATTAGLIARIN, DAOLIO. Novel Au/La1?xSrxMnO3 and Au/La1?xSrxCrO3composites: Catalytic activity for propane partial oxidation and reforming [J]. Solid State Ionics, 2007, 177: 3473-3484.
[38] JIANG S P. Issues on development of (La, Sr)MnO3 cathode for solid oxide fuel cells[J]. Journal of Power Sources, 2003, 124: 390-402.
[39] MARC M, GROFFREY, OZIN A. LSM/YSZ nanocomposites derived from a surfactant assisted, co-assembled mesoporous phase [J]. Journal of American Chemical Society, 2003, 125: 5161-5175.
[40] SHAO Z, HAILE M. A high-performance cathode for the next generation of solid oxide fuel cells [J]. Nature, 2004, 431:170-173.
[41] SHAO Z, XIONG H. Performance of a mixed-conducting ceramic membrane reactor with high oxygen permeability for methane conversion [J]. Journal of Membrane Science, 2001, 183: 181-192.
[42] WANG Y, WANG S, WANG Z. Performance of Ba0.5Sr0.5Co0.8Fe0.2O3?δ-CGO-Ag cathode for IT-SOFC [J]. Journal of Alloys and Compounds, 2007, 428: 286-289.
[43] LI S, LU Z, WEI B, et al. (Ba0.5Sr0.5)1?xSmxCo0.8Fe0.2O3?δas a cathode material for IT-SOFC[J]. Journal of Alloys and Compounds, 2006, 426: 408-414.
[44] HIGUCHI T, TSUKAMOTO T, SATA N, et al. Photoemission study on photonic conductor p-type SrTiO3 [J]. Solid State Ionics, 1998, 108: 349-353.
[45] SZOT K, SPEIER W, HERION J. Restructuring of surface region in SrTiO3 [J]. Applied physics A, 1997, 64:55-59.
[46] HUI S, PETRIC A. Electrical Properties of Y-doped SrTiO3 under Reducing conditions [J]. Journal of Electrochemical Society, 2002, 149: 1-10.
[47] FRAYRET C, VILLESUZANNE A, POUCHARD M. Application of density functional theory to the modeling of the mixed ionic and electronic conductor La2NiO4+δ[J]. Chemical Materials, 2005, 17: 6538-6544.
[48] KHARTON V V, VISKUP A, KOVALEVSKY A V, et al. Ionic transport in oxygen-hyperstoichiometric phases with K2NiF4-type structure [J]. Solid State Ionics, 2001, 143: 337-353.
[49] KHARTON V V, KOVALEVSKY A V, AVDEEV M, et al. Chemically induced expansion of La2NiO4+δ-based materials [J]. Chemical Materials, 2007, 19: 2027-2033.
[50] AGUAADERO A, ALONSO J A, DAZA L. Hyperstoichiometric La1.9Sr0.1NiO4+δmixed conductor as novel cathode for intermediate temperature SOFC [J]. Journal of Fuel Cell Science and Technology, 2007, 4: 294-298.
[51] MAZANEC T J, CABLE T L. Electro catalytic cells for chemical reaction [J]. Solid State Ionics,1992,53-56:111-118.
[52] CHEN C.S, RUIDHOF H.K. Oxygen permeation and through oxygen ion oxide-noble metal dual phase composites [J]. Solid State Ionics, 1996, 86-88:569-597.
[53] CUI H, PAL U B. CGO-YST compsite mixed conductors for hydrogen separation [J]. Journal of Electrochemical Society, 2005, 152: 1726-1732.
[54] INABA H, NAKAJIMA T, TAGAWA H. Sintering behaviors of ceria and gadolinia-doped ceria [J]. Solid State Ionics, 1998, 106: 263-268.
[55] ZHANG T S,HING P,HUANG H T, et al. Densification, microstructure and grain growth in the CeO2–Fe2O3 system [J]. Journal of the European Ceramic Society, 2001, 21: 2221-2228.
[56] YOSHIDA H,MIURAK, FUJITA J, et al. Effect of Gd addition on the sintering behavior of samaria-doped ceria [J]. Journal of the American Ceramic Society, 1999, 82: 219-221.
[57] GHOSH A, HALDAR M K, DAS K. Effect of MgO and ZrO2 additions on the properties of magnesite-chrome composite refractory[J].Ceramics International, 2007, 33: 821-825.
[58] KLEINLOGEL C, GAUCKLER L J. Sintering and properties of nanosized Ceria solid solutions [J]. Solid State Ionics, 2000, 135:567-573.
[59] DU X L, QIN M L , FARID A, et al. Study of rare-earth oxide sintering aid systems for AlN ceramics [J]. Materials Science and Engineering, 2007, 460-461: 471-474.
[60] KLEINLOGEL C, GAUCKLER L J.Sintering of nanocrystalline CeO2 ceramics [J]. Advanced Materials, 2001, 13: 1081-1085.
[61] KLEINLOGEL C, GAUCKLER L J. Mixed electronic-ionic conductivity of cobalt doped cerium gadolinium oxide [J]. Journal of Electroceram, 2000, 5: 231-243.
[62] ZHANG T S, HING P, HUANG H T, et al. Sintering and grain growth of CoO-doped CeO2 ceramics [J]. Journal of the European Ceramic Society, 2002, 22: 27-34.
[63] GIL V, TARTALJ J, MOURE C, et al. Rapid densification by using Bi2O3 as an aid for sintering of gadolinia-doped ceria ceramics [J]. Ceramics International, 2007, 33: 471-475.
[64] LEE J S, CHOIK H, RYU B, et al. Effects of alumina additions on sintering behavior of gadolinia-doped ceria [J]. Ceramics International, 2004, 30: 807-812.
[65] NICHOLAS J D, JONGHE L D. Prediction and evaluation of sintering aids for Creium Gadolinium oxide [J]. Solid State Ionics, 2007, 178: 1187-1194.
[66] BADWAL S P. Grain boundary resistivity in zirconia-based materials: effect of sintering temperatures and impurities [J]. Solid State Ionics, 1995, 76(1-2): 67-80.
[67] JIANG K, HE Z Q, MENG J, et al. Low temperature preparation and fuel cell properties of rare earth doped barium cerate solid electrolytes [J]. Science in China (B), 1999, 42(3): 298-304.
[68] LEWIS G S, ATKINSON A, STEEL B C, et al. Effect of Co addition on the lattice parameter, electrical conductivity and sintering of gadolinia-doped ceria [J]. Solid State Ionics, 2002, 152-153: 567-573.
[69] PéRZE D, Nú?EZ P, ABRANTES J C, et al. Effects of firing conditions and addition of Co on bulk and grain boundary properties of CGO [J]. Solid State Ionics, 2005, 176: 2799-2804.
[70] JOON H K, GYEONG M C. Mixed ionic and electronic conductivity of YSZ-MnO [J] .Solid State Ionics, 2000:130,157-168.
[71] MCEVOY A. J. Thin SOFC electrolytes and their interfaces [J]. Solid State Ionics, 2000,132 :159-165
[72] RIESS I. Mixed ionic-electronic conductors- material properties and applications [J]. Solid State Ionics, 2003, 157 :1-17
[73] SHAULA A, KHARTON V, MARQUES F, et al. Oxygen permeability of mixed-conducting composite membranes [J]. Journal of Solid State Electrochemistry, 2006, 10: 28–40.
[74] KUROKAWA H, LIMING Y, CRAIG P, et al. Y-doped SrTiO3 based sulfur tolerant anode for solid oxide fuel cells[J]. Journal of Power Sources, 2007,164 :510-518.
[75] GARZON.Compiler:US,5,543,025[P/OL].1996-08-06.[1996-08-02].http://www.pat2pdf.org /patents/pat5543025.pdf
[76] TAKEUCHI T. Oxygen sensors [J]. Sensors and Actuators, 1988, 14: 109-124.
[77] SAJI K, KONDO H, TAKAHASHI H, et al. Development of a thin-film oxygen sensor for combustion control of gas appliances [J]. Sensors and Actuators B, 1993, 13–14:695–696.
[78] WOLFGANG, REINHARDT G, MARTIN R. Trends in the development of solid state amperometric and potentiometric high temperature sensors [J]. Solid State Ionics, 2000, 136–137:519–531.
[79] LEE J H, KWON C S, KIM H, et al. Limiting current characteristics with regard to oxygen and carbon monoxide in oxidizing and reducing atmospheres [J]. Solid State Ionics, 1996, 86-88:1087-1093.
[80] PENG Z, LIU M, BALKO E. A new type of amperometric oxygen sensor based on a mixed-conducting composite membrane [J]. Sensors and Actuators B, 2001, 72: 35-40.
[81] INABA T, SAJI K. Low temperature operation of thin-film limiting-current type oxygen sensor using graded-composition layer electrodes [J]. Sensors and Actuators B, 2008, 129: 874-880.
[82] LEE J H, KWON C S, KIM H, et al. Limiting current and wide range air/fuel ratio sensors using the same YSZ-Al2O3 layers as electrolyte and diffusion barrier [J]. Sensors and Actuators B, 1996, 36:278-284.
[83]李福燊,杨媚,吴卫江.用LSCo作扩散障碍层的极限电流型氧传感器[J].北京科技大学学报,2006,26(5):495-497.
[84] WANG L, KUMAR R V. Thick film miniaturized HCl gas sensor [J]. Sensors and Actuators B, 2004,98: 196-203.
[85] WANG L, KUMAR R V. Thick film CO2 sensors based on Nasicon solid electrolyte [J]. Solid State Ionics, 2003, 158: 309– 315.
[86] LEE J H, KWON C S, KIM H, et al. Oxygen sensing characteristics of limiting current-typesensors with micro structural and structural variations in diffusion barrier [J]. Materials Letters, 1996, 26:27-33.
[87] EGUCHI Y, WATANABE S, KUBOTA N, et al. A limiting current type sensor for hydrocarbons [J]. Sensors and Actuators B, 2000, 66:9-11.