Pt/SiO2-Al2O3抗硫型柴油车尾气净化氧化催化剂的制备及性能
Preparation and properties of the Pt/SiO2-Al2O3 sulfur resistance diesel oxidation catalyst
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摘要: 使用浸渍法制备了一系列SiO2含量不同的改性Al2O3材料，并以此为载体制得一系列Pt/SiO2-Al2O3柴油车尾气净化氧化催化剂（DOC）.N2吸附-脱附实验和扫描电子显微镜（SEM）检测证实，SiO2以多孔形式均匀覆盖在Al2O3表面，没有明显影响Al2O3的织构性质.运用热重法对各催化剂的抗硫性进行了表征，结果证实，SiO2的引入有效提高了Pt/Al2O3催化剂的抗硫性；经硫累积实验后，所制备的Pt/SiO2-Al2O3系列催化剂硫酸盐累积量均小于1.0 wt.%，而Pt/Al2O3的硫酸盐累积量约为3.94 wt.%.催化剂活性检测结果表明，适量SiO2的引入不会影响Pt/Al2O3催化剂的活性；当SiO2引入量为18 wt.%时，Pt/SiO2（18%）-Al2O3催化剂不仅抗硫性能优异而且具有更好的耐久性，模拟柴油车使用160000 km后，其催化活性未明显降低.因此，本研究认为SiO2在Pt/Al2O3 DOC催化体系中，可以起着抑制硫中毒及提高耐久性的作用.Abstract: A series of SiO2 modified Al2O3 mixed materials with different SiO2 content were prepared by using impregnation method, and then used as supports to prepare Pt/SiO2-Al2O3 diesel oxidation catalysts (DOC). N2 adsorption-desorption isotherm and scanning electron microscopy (SEM) results indicate that SiO2 was porous and covered on the surface of Al2O3 uniformly, which did not obviously affect the texture properties of Al2O3 support. The thermo-gravimetric analysis (TGA) was employed to characterize the sulfur resistance of as-prepared catalysts, which demonstrated that the introduction of SiO2 efficiently enhanced the sulfur resistance of Pt/Al2O3 catalyst. After SO2 uptake experiment, the amount of cumulated sulfur over the Pt/SiO2-Al2O3 catalysts was less than 1.0 wt.%; while it was about 3.94 wt.% on the Pt/Al2O3 catalyst. The activity measurements suggest that the introduction of SiO2 did not obviously affect the activity of Pt/Al2O3 catalyst. When the SiO2 concentration was 18 wt.%, the Pt/SiO2(18%)-Al2O3 catalyst displayed outstanding sulfur resistance and durability. Moreover, the 160000 km vehicle aging simulation did not reduce the catalytic performance of Pt/SiO2(18%)-Al2O3 obviously. Thus, this study implies that SiO2 in the Pt/Al2O3 DOC catalyst can play important roles in inhibiting the sulfur poisoning and enhancing the durability.
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[1] YANG Z, ZHANG N, CAO Y, et al. Effect of yttria in Pt/TiO2 on sulfur resistance diesel oxidation catalysts:enhancement of low-temperature activity and stability[J]. Catal Sci Technol, 2014, 4:3032-3043. [2] 胡冬梅, 彭林, 白慧玲, 等. 高等植物、燃煤和机动车排放正构烷烃特征分析[J]. 环境化学, 2014, 33(5):716-723. HU D M, PENG L, BAI H L, ed al. Characteristics of n-alkanes emissions from higer plants, coal ashes and vehicles[J]. Environmental Chemistry, 2014, 33(5):716-723(in Chinese).
[3] 李友平, 范忠雨, 李坤, 等. 不同出行方式PM2.5个体暴露及其影响因素[J]. 环境化学, 2015, 34(8):1408-1416. LI Y P, FAN Z Y, LI K, et al. Commuter exposure to PM2.5and its influencing factors in different commuting modes[J]. Environmental Chemistry, 2015, 34(8):1408-1416(in Chinese).
[4] JOHNSON T. Vehicular emissions in review[J]. SAE Technical Paper, 2014, 2014-01-1491. [5] VERDIER S, ROHART E, LARCHER O, et al. Innovative materials for diesel oxidation catalysts, with high durability and early light-off[J]. SAE Technical Paper, 2005, 2005-01-0476. [6] RUSSELL A, EPLING W S. Diesel oxidation catalysts[J]. Catal Rev, 2011, 53(4):337-423. [7] POPOVA N M, UMBETKALIEV A K, DOSUMOV K, et al. Interaction of SO2 with O2 over mixed Pt, Pd, Pt-Pd and Pt-Ru oxidation catalysts and combined treatment of automobile exhaust gases[J]. React Kinet Catal L, 1996, 57(2):255-262. [8] GALISTEO F C, MARISCAL R, GRANADOS M L, et al. Reactivation of a commercial diesel oxidation catalyst by acid washing[J]. Environ Sci Technol, 2005, 39(10):3844-3848. [9] GALISTEO F C, MARISCAL R, GRANADOS M L, et al. Reactivation of sulphated Pt/Al2O3 catalysts by reductive treatment in the simultaneous oxidation of CO and C3H6[J]. Appl Catal B:Environ, 2007, 72(3-4):272-281. [10] ZHONG F L, ZHONG Y J, XIAO Y H, et al. Sulfur resistance and activity of Pt/CeO2-ZrO2-La2O3 diesel oxidation catalysts[J]. Chin J Catal, 2011, 32(9):1469-1476. [11] YANG Z Z, YANG Y, ZHAO M, et al. Enhanced sulfur resistance of Pt-Pd/CeO2-ZrO2-Al2O3 commercial diesel oxidation catalyst by SiO2 surface cladding[J]. Acta Phys-Chim Sin, 2014, 30(6):1187-1193. [12] LEE K, LEE E, SONG C, et al. Density functional theory study of propane steam reforming on Rh-Ni bimetallic surface:Sulfur tolerance and scaling/Brønsted-Evans-Polanyi relations[J]. J Catal, 2014, 309:248-259. [13] TAN P Q, HU Z Y, LOU D M. Regulated and unregulated emissions from a light-duty diesel engine with different sulfur content fuels[J]. Fuel, 2009, 88(6):1086-1091. [14] ZHANG K, HU J, GAO S, et al. Sulfur content of gasoline and diesel fuels in northern China[J]. Energy Policy, 2010, 38(6):2934-2940. [15] CORRO G. Sulfur impact on diesel emission control-A review[J]. React Kinet Catal L, 2002, 75(1):89-106. [16] ZELENKA P, OSTGATHE K, LOX E. Reduction of diesel exhaust emissions by using oxidation catalysts[J]. SAE Technical Paper, 1990, 902111. [17] LI J, KUMAR A, CHEN X, et al. Impact of different forms of sulfur poisoning on diesel oxidation catalyst performance[J]. SAE Technical Paper, 2013, doi:10.4274/2013-01-0514. [18] KANNO Y, HIHARA T, WATANABE T, et al. Low sulfate generation diesel oxidation catalyst[J]. SAE Technical Paper, 2004, doi:10.4274/2004-01-1427. [19] 杨铮铮, 陈永东, 赵明, 等. 具有低SO2氧化活性的Pt/ZrxTi1-xO2柴油车氧化催化剂的制备及性能[J]. 催化学报, 2012, 33(5):819-826. YANG Z Z, CHEN Y D, ZHAO M, et al. Preparation and properties of Pt/ZrxTi1-xO2 catalysts with low-level SO2 oxidation activity for diesel oxidation[J]. Cuihua Xuebao (Chin J Catal), 2012, 33(5):819-826(in Chinese).
[20] YANG Z, LI J, ZHANG H, et al. Size-dependent CO and propylene oxidation activities of platinum nanoparticles on the monolithic Pt/TiO2-YOx diesel oxidation catalyst under simulative diesel exhaust conditions[J]. Catal Sci Technol, 2015, 5:2358-2365. [21] 周菊发, 赵明, 彭娜, 等. Pt/MOx-SiO2 (M=Ce, Zr, Al)催化剂对CO和C3H8氧化性能的影响[J]. 物理化学学报, 2012, 28(6):1448-1454. ZHOU J F, ZHAO M, PENG N, et al. Performance effect of Pt/MOx-SiO2 (M=Ce, Zr, Al) catalysts for CO and C3H8 oxidation[J]. Acta Phys-Chim Sin, 2012, 28(6):1448-1454(in Chinese).
[22] YANG J, MEI S, FERREIRA J M. Hydrothermal synthesis of nanosized titania powders:Influence of peptization and peptizing agents on the crystalline phases and phase transitions[J]. J Am Ceram Soc, 2000, 83(6):1361-1368. [23] PORTER J F, LI Y G, CHAN C K. The effect of calcination on the microstructural characteristics and photoreactivity of Degussa P-25 TiO2[J]. J Mater Sci, 1999, 34(7):1523-1531. [24] KAŠPAR J, FORNASIERO P, HICKEY N. Automotive catalytic converters:Current status and some perspectives[J]. Catal Today, 2003, 77(4):419-449. [25] KORANNE M M, PRYOR J N. Sulfur tolerant alumina catalyst support[P]. US Patent, 2012, 8158257. [26] ADAMS K M, CAVATAIO J V, HAMMERLE R H, Lean NOx catalysis for diesel passenger cars:Investigating effects of sulfur dioxide and space velocity[J]. Appl Catal B:Environ, 1996, 10(1):157-181. [27] GRUBERT G, NEUBAUER T, PUNKE A H, et al. Diesel oxidation catalyst composite with layer structure for carbon monoxide and hydrocarbon conversion[J]. US Patent, 2014, 8211392. [28] BENTELE A, WANNINGER K, MALETZ G, et al. Diesel oxidation catalyst with good low-temperature activity[P]. US Patent, 2014, 8859454. [29] ANDERSSON J, ANTONSSON M, EURENIUS L, et al. Deactivation of diesel oxidation catalysts:Vehicle- and synthetic aging correlations[J]. Appl Catal B:Environ, 2007, 72(1-2):71-81. [30] WINKLER A, FERRI D, AGUIRRE M, The influence of chemical and thermal aging on the catalytic activity of a monolithic diesel oxidation catalyst[J]. Appl Catal B:Environ, 2009, 93(1-2):177-184. [31] KIM J, KIM C, CHOUNG S J. Comparison studies on sintering phenomenon of diesel oxidation catalyst depending upon aging conditions[J]. Catal Today, 2012, 185(1):296-301. [32] UENO H, FURUTANI T, NAGAMI T, et al. Development of catalyst for diesel engine[J]. SAE Technical Paper, 1998, 980195. [33] PAULSON T, MOSS B, TODD B, et al. New Developments in Diesel Oxidation Catalysts[J]. SAE Technical Paper, 2008, doi:10.4274/2008-01-2638. [34] XU H, ZHANG Q, QIU C, et al. Tungsten modified MnOx-CeO2/ZrO2 monolith catalysts for selective catalytic reduction of NOx with ammonia[J]. Chem Eng Sci, 2012, 76:120-128. [35] ZIGLER G, HASSELMAN D. Effect of phase composition and microstructure on the thermal diffusivity of silicon nitride[J]. J Mater Sci, 1981, 16:495-503. [36] LITOVSKY E, SHAPIRO M, SHAVIT A. Gas pressure and temperature dependences of thermal conductivity of porous ceramic materials:Part 2, refractories and ceramics with porosity exceeding 30%[J]. J Am Ceram Soc, 1996, 79:1366-1376. -
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