Probing NH3-SCR catalytic activity and SO2 resistance over aqueous-phase synthesized Ce-W@TiO2 catalyst
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摘要: 采用水相法制备了Ce、W、Ti复合氧化物催化剂并用于氨选择性催化还原NO (NH3-SCR) 过程。TiO2包裹型Ce-W@TiO2催化剂表现出最佳的催化活性。205-515℃ NO转化率超过90%。SO2的存在造成所有催化剂低温段NO催化转化率的降低和高温段 (425-540℃) NO催化转化率的升高, TiO2@Ce-W表现出优越的低温抗SO2性能。通过普通共沉淀法向Ce-W复合氧化物中引入Ti会导致催化剂表面W丰度、酸性位点的减少和低温NO转化率、耐SO2性能的降低。通过水相法制备的TiO2包裹型的Ce-W@TiO2型催化剂, 有利于表面W丰度、酸性位点、低温抗SO2性能和催化活性的提高。Abstract: A series of mixed Ce, W and Ti oxides catalysts have been prepared and employed to selective catalytic reduction of NO with ammonia (NH3-SCR).It was found that Ce-W@TiO2 exhibited the optimal catalytic activity.Over 90% of NO conversion could be obtained by the surface TiO2-coated Ce-W@TiO2 catalyst at 205-515℃.The presence of SO2 leads to a decrease of low-temperature NO catalytic conversion and an increase of NO conversion above 425℃ over various catalysts, while Ce-W@TiO2 exhibits the optimal low-temperature SO2 resistance.It is noted that introducing Ti into Ce-W mixed oxide via the conventional co-precipitation method attributed to the decrease of surface W atomic abundance and acidic sites as well as inferior low-temperature NO conversion and SO2 resistance.In contrast, the surface TiO2-coated Ce-W@TiO2 catalyst prepared via a modified aqueous-phase method exhibit increased surface W atomic abundance and acidic sites as well as the superior low-temperature NO conversion and SO2 resistance.
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Key words:
- aqueous-phase method /
- NH3-SCR /
- Ce-W@TiO2 /
- NO conversion /
- SO2 resistance
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图 1 Ce-W、Ce-Ti-W、Ce-W@TiO2催化剂的SCR活性评价 (a) 及抗硫性测试 (b)
Figure 1. Catalytic activity over Ce-W, Ce-Ti-W and Ce-W@TiO2 catalysts in the presence (a) and abesence of SO2(b)
(reaction condition: 0.080% NO, 0.080% NH3, 5%O2, 0.020% SO2, N2 balanced, GHSV=60000h-1)
图 2 不同浓度SO2对Ce-W@TiO2催化剂的NH3-SCR活性的影响
Figure 2. Influence of different SO2 concentrations on NH3-SCR activity over Ce-W@TiO2 catalyst
(reaction condition: 0.080% NO, 0.080% NH3, 5% O2, 0.005% to 0.020% SO2, N2 balanced, GHSV=60000h-1)
图 3 Ce-W、Ce-W@TiO2、Ce-Ti-W催化剂的XRD谱图
Figure 3. XRD patterns of Ce-W, Ce-Ti-W and Ce-W@TiO2 catalysts
图 4 Ce-W、Ce-Ti-W、Ce-W@TiO2催化剂的Ce 3d XPS谱图
Figure 4. XPS spectra of Ce 3d over Ce-W, Ce-Ti-W and Ce-W@TiO2 catalysts
图 5 Ce-W、Ce-Ti-W、Ce-W@TiO2催化剂的O 1s XPS谱图
Figure 5. XPS spectra of O 1s over Ce-W, Ce-Ti-W and Ce-W@TiO2 catalysts
图 6 Ce-W、Ce-Ti-W、Ce-W@TiO2催化剂的W 4f XPS谱图
Figure 6. XPS spectra of W 4f over Ce-W, Ce-Ti-W and Ce-W@TiO2 catalysts
图 7 Ce-W、Ce-Ti-W、Ce-W@TiO2催化剂的Ti 2p XPS谱图
中文注解
Figure 7. XPS spectra of Ti 2p over Ce-W, Ce-Ti-W and Ce-W@TiO2 catalysts
英文注解
图 8 Ce-W、Ce-Ti-W、Ce-W@TiO2催化剂的H2-TPR谱图
Figure 8. H2-TPR profiles of Ce-W, Ce-Ti-W and Ce-W@TiO2 catalysts
图 9 Ce-W、Ce-Ti-W、Ce-W@TiO2催化剂的NH3-TPD谱图
Figure 9. NH3-TPD profiles of Ce-W, Ce-Ti-W and Ce-W@TiO2
表 1 Ce-W、Ce-Ti-W、Ce-W@TiO2催化剂表面原子丰度
Table 1. Surface atomic concentration of Ce-W, Ce-Ti-W and Ce-W@TiO2
Sample Surface atomic concentrations w/% Ce Ti W O Ce4+/(Ce3+ + Ce4+) Oα/(Oα+ Oβ) Ce-W 18.04 - 19.52 62.44 76.6 65.2 Ce-W@TiO2 7.47 15.77 11.91 64.85 68.4 62.7 Ce-Ti-W 16.94 12.46 8.61 61.99 63.2 60.8 
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[1] 刘亚明, 束摇航, 徐齐胜, 张玉华, 杨林军.SCR脱硝过程中SO2催化氧化的原位红外研究[J].燃料化学学报, 2015, 43(8):1018-1024. doi: 10.1016/S1872-5813(15)30030-XLIU Ya-ming, SHU Hang, XU Qi-sheng, ZHANG Yu-hua, YANG Lin-jun.FT-IR study of the catalytic oxidation of SO2 during the process of selective catalytic reduction of NO with NH3 over commercial catalysts[J].J Fuel Chem Technol, 2015, 43(8):1018-1024). doi: 10.1016/S1872-5813(15)30030-X [2] GARCÍA-BORDEJÉ E, CALVILLO L, LÁZARO M J, MOLINER R.Vanadium supported on carbon-coated monoliths for the SCR of NO at low temperature:Effect of pore structure[J].Appl Catal B:Environ, 2004, 50(4):235-242. doi: 10.1016/j.apcatb.2004.01.008 [3] BRANDENBERGER S, KRÖCHER O, TISSLER A, ALTHOFF R.The state of the art in selective catalytic reduction of NOx by ammonia using metal-exchanged zeolite catalysts[J].Catal Rev:Sci Eng, 2008, 50(4):492-531. doi: 10.1080/01614940802480122 [4] GU T T, JIN R B, LIU Y, LIU H F, WENG X L, WU Z B.Promoting effect of calcium doping on the performances of MnOx/TiO2 catalysts for NO reduction with NH3 at low temperature[J].Appl Catal B:Environ, 2013, 129:30-38. doi: 10.1016/j.apcatb.2012.09.003 [5] LI J H, CHEN J J, KE R, LUO C K, HAO J M.Effect of precursors on the surface Mn species and the activities for NO reduction over MnOx/TiO2 catalyst[J].Catal Commun, 2007, 8(12):1896-1900. doi: 10.1016/j.catcom.2007.03.007 [6] LI J H, CHANG H Z, MA L, HAO J M, YANG R T.Low-temperature selective catalytic reduction of NOx with NH3 over metal oxide and zeolite catalysts-A review[J].Catal Today, 2011, 175(1):147-156. doi: 10.1016/j.cattod.2011.03.034 [7] KOEBEL M, ELSENER M, KLEEMANN M.Urea-SCR:A promising technique to reduce NOx emissions from automotive diesel engines[J].Catal Today, 2000, 59(3/4):335-345. [8] PENG Y, LI K Z, LI J H.Identification of the active sites on CeO2-WO3 catalysts for SCR of NOxwith NH3:An in situ IR and Raman spectroscopy study[J].Appl Catal B:Environ, 2013, 140-141:483-492. doi: 10.1016/j.apcatb.2013.04.043 [9] LIU F D, YU Y B, HE H.Environmentally-benign catalysts for the selective catalytic reduction of NOx from diesel engines:Structure-activity relationship and reaction mechanism aspects[J].Chem Commun, 2014, 50(62):8445-8463. doi: 10.1039/C4CC01098A [10] GAO X, JIANG Y, ZHONG Y, LUO Z Y, CEN K F.The activity and characterization of CeO2-TiO2 catalysts prepared by the sol-gel method for selective catalytic reduction of NO with NH3[J].J Hazard Mater, 2010, 174(1/3):734-739. [11] GAO X, JIANG Y, FU Y C, ZHONG Y, LUO Z Y, CEN K F.Preparation and characterization of CeO2/TiO2 catalysts for selective catalytic reduction of NO with NH3[J].Catal Commun, 2010, 11(5):465-469. doi: 10.1016/j.catcom.2009.11.024 [12] ZHANG Q L, SONG Z X, NING P, LIU X, LI H, GU J J.Novel promoting effect of acid modification on selective catalytic reduction of NO with ammonia over CeO2 catalyst[J].Catal Commun, 2015, 59:170-174. doi: 10.1016/j.catcom.2014.10.007 [13] LIU Z M, LIU Y X, LI Y, SU H, MA L L.WO3 promoted Mn-Zr mixed oxide catalyst for the selective catalytic reduction of NOx with NH3[J].Chem Eng J, 2016, 283:1044-1050. doi: 10.1016/j.cej.2015.08.040 [14] SHAN W P, LIU F D, HE H, ZHANG C B.A superior Ce-W-Ti mixed oxide catalyst for the selective catalytic reduction of NOx with NH3[J].Appl Catal B:Environ, 2012, 115-116:100-106. doi: 10.1016/j.apcatb.2011.12.019 [15] 徐颖, 闫东杰, 黄学敏, 玉亚, 刘树军.制备方法对Mn-Ce/TiO2催化剂低温选择性催化还原活性的影响[J].环境工程学报, 2015, 9(2):862-866. http://www.cnki.com.cn/Article/CJFDTOTAL-HJJZ201502058.htmXU Ying, YAN Dong-jie, HUANG Xue-min, YU Ya, LIU Shu-jun.Effects of preparation methods of Mn-Ce/TiO2 catalyst on low temperature SCR activity[J].Chin J Environ Eng, 2015, 9(2):862-866). http://www.cnki.com.cn/Article/CJFDTOTAL-HJJZ201502058.htm [16] NING P, SONG Z X, LI H, ZHANG Q L, LIU X, ZHANG J H, TANG X S, HUNG Z Z.Selective catalytic reduction of NO with NH3 over CeO2-ZrO2-WO3 catalysts prepared by different methods[J].Appl Surf Sci, 2015, 332:130-137. doi: 10.1016/j.apsusc.2015.01.118 [17] XU N, YE J W, TANG Y B, MAN C Z, HE G L, YE H, NIN G L.Solvent assisted morphology-controlled synthesis of CeO2 micro/nanostructures[J].Mater Lett, 2012, 82:199-20. doi: 10.1016/j.matlet.2012.05.062 [18] FRANCISCO M S P, MASTELARO V R.Activity and characterization by XPS, HR-TEM, Raman spectroscopy, and BET surface area of CuO/CeO2-TiO2 catalysts[J].J Phys Chem B, 2001, 105(43):10515-10522. doi: 10.1021/jp0109675 [19] GAO R H, ZHANG D S, MAITARAD P, SHI L Y, RUNGROTMONGKOL T, LI H, ZHANG J P, CAO W G.Morphology-dependent properties of MnOx/ZrO2-CeO2 nanostructures for the selective catalytic reduction of NO with NH3[J].J Phys Chem C, 2013, 117(20):10502-10511. doi: 10.1021/jp400984z [20] LARSSON P O, ANDERSSONY A.Complete oxidation of CO, ethanol, and ethyl acetate over copper oxide supported on titania and ceria modified titania[J].J Catal, 1998, 179(1):72-89. doi: 10.1006/jcat.1998.2198 [21] ERNST B, HILAIRE L, KIENNEMANN A.Effects of highly dispersed ceria addition on reducibility, activity and hydrocarbon chain growth of a Co/SiO2 Fischer-Tropsch catalyst[J].Catal Today, 1999, 50(2):413-427. doi: 10.1016/S0920-5861(98)00519-7 [22] THROMAT N, GAUTIER-SOYER M, BORDIER G.Formation of the Ce/Y2O3 interface:An in situ XPS study[J].Surf Sci, 1996, 345(3):290-302. doi: 10.1016/0039-6028(95)00883-7 [23] NORMAND F, HILAIRE L, KILI K, KRILL G, MAIRE G.Oxidation state of cerium in cerium-based catalysts investigated by spectroscopic probes[J].J Phys Chem, 1988, 92(9):2561-2568. doi: 10.1021/j100320a033 [24] 戴韵, 李俊华, 彭悦, 唐幸福.MnO2的晶相结构和表面性质对低温NH3-SCR反应的影响[J].物理化学学报, 2012, 28(7):1771-1776. http://www.cnki.com.cn/Article/CJFDTOTAL-WLHX201207032.htmDAI Yun, LI Jun-hua, PENG Yue, TANG Xing-fu.Effects of MnO2 crystal structure and surface property on the NH3-SCR reaction at low temperature[J].Acta Phys Chim Sin, 2012, 28(7):1771-1776. http://www.cnki.com.cn/Article/CJFDTOTAL-WLHX201207032.htm [25] KANG M, PARK E D, KIM J M, YIE J E.Manganese oxide catalysts for NOx reduction with NH3 at low temperatures[J].Appl Catal A:Gen, 2007, 327(2):261-269. doi: 10.1016/j.apcata.2007.05.024 [26] CHEN L, LI J H, ABLIKIM W, WANG J, CHANG H Z, MA L, XU J Y, GE M F, ARANDIYAN H.CeO2-WO3 mixed oxides for the selective catalytic reduction of NOx by NH3 over a wide temperature range[J].Catal Lett, 2011, 141(12):1859-1864. doi: 10.1007/s10562-011-0701-4 [27] YANG S X, ZHU W P, JIANG Z P, CHEN Z X, WANG J B.The surface properties and the activities in catalytic wet air oxidation over CeO2-TiO2 catalysts[J].Appl Surf Sci, 2006, 252(24):8499-8505. doi: 10.1016/j.apsusc.2005.11.067 [28] ENGELMANN-PIREZ M, GRANGER P, LECLERCQ G.Investigation of the catalytic performances of supported noble metal based catalysts in the NO+H2 reaction under lean conditions[J].Catal Today, 2005, 107-108:315-322. doi: 10.1016/j.cattod.2005.07.087 [29] ZHANG Q L, LIU X, NING P, SONG Z X, LI H, GU J J.Enhanced performance in NOx reduction by NH3 over a mesoporous Ce-Ti-MoOx catalyst stabilized by a carbon template[J].Catal Sci Technol, 2015, 5(4):2260-2269. doi: 10.1039/C4CY01371A -
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