Promoting effect of transition metal on low-temperature deNOx activity of CeO2@TiO2 catalyst for selective catalytic reduction
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摘要: 采用过渡金属M（M=Mn、Co、Fe和Cu）掺杂改性自发沉积策略制备的非晶态CeO2@TiO2催化剂，考察M-CeO2@TiO2选择性催化还原NOx的低温活性，并通过XRD、TEM、N2吸附-脱附、H2-TPR、NH3-TPD及in-situ FT-IR等表征手段研究M-CeO2@TiO2的结构、表面性质以及低温NH3-SCR反应过程。结果表明，M-CeO2@TiO2具有更优异的低温氧化还原能力以及更多的表面酸量，且Cu掺杂对CeO2@TiO2选择性催化还原NOx低温活性具有最为显著的促进作用。Cu-CeO2@TiO2催化剂在低温NH3-SCR反应过程中同时存在E-R机理和L-H机理，但是由于"快速SCR"使得L-H机理反应起关键作用。Abstract: Transition metal M(M=Mn, Co, Fe and Cu) modified amorphous CeO2@TiO2 catalysts were prepared via a spontaneous deposition strategy. The low-temperature deNOx activity of M-CeO2@TiO2 for selective catalytic reduction was investigated. XRD, TEM, N2 adsorption-desorption, H2-TPR, NH3-TPD and in-situ FT-IR were used to study the structure, surface property and low-temperature NH3-SCR reaction performance of M-CeO2@TiO2. The results showed that the M-CeO2@TiO2 had better low-temperature oxidation reducibility and more surface acid. Cu doping had the most significant promoting effect on low-temperature deNOx activity for selective catalytic reduction. During the low-temperature NH3-SCR reaction, both the L-H and E-R mechanisms existed over the Cu-CeO2@TiO2 and the L-H mechanism could play a pivotal role due to the "fast SCR"process.
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图 3 催化剂的TEM照片
Figure 3 TEM images of the catalysts
(a): CeO2@TiO2; (b): Mn-CeO2@TiO2; (c): Co-CeO2@TiO2; (d): Fe-CeO2@TiO2; (e): Cu-CeO2@TiO2
图 4 催化剂的N2吸附-脱附等温线和孔径分布
Figure 4 N2 adsorption-desorption isotherms and pore size distributions of the catalysts
图 7 CeO2@TiO2和Cu-CeO2@TiO2催化剂对于NH3吸附饱和的原位红外光谱谱图
Figure 7 In-situ FT-IR spectra of NH3 adsorption over CeO2@TiO2 (a) and Cu-CeO2@TiO2 (b)
图 8 CeO2@TiO2和Cu-CeO2@TiO2催化剂对于NO+O2吸附饱和的原位红外光谱谱图
Figure 8 In-situ FT-IR spectra of NO+O2 adsorption over CeO2@TiO2 (a) and Cu-CeO2@TiO2 (b)
图 9 CeO2@TiO2和Cu-CeO2@TiO2催化剂在150 ℃饱和吸附NH3后通入NO+O2的原位红外光谱谱图
Figure 9 In-situ FT-IR spectra of NO+O2 reacted with pre-adsorbed NH3 over CeO2@TiO2 (a) and Cu-CeO2@TiO2 (b) at 150 ℃
图 10 CeO2@TiO2和Cu-CeO2@TiO2催化剂在150 ℃饱和吸附NO+O2后通入NH3的原位红外光谱谱图
Figure 10 In-situ FT-IR spectra of NH3 reacted with pre-adsorbed NO+O2 over CeO2@TiO2 (a) and Cu-CeO2@TiO2 (b) at 150 ℃
表 1 催化剂的物理化学性质
Table 1 Physical chemical properties of the catalysts
Catalyst ABET/
(m2·g-1)vp/
(cm3·g-1)dp/
nmH2 consumption/
(cm3·gcat-1)Acid amount/
(mmol·gcat-1)CeO2@TiO2 210.03 0.258 5 4.923 9 53.28 0.164 6 Mn-CeO2@TiO2 123.59 0.189 2 6.123 6 55.62 0.181 7 Co-CeO2@TiO2 120.74 0.181 0 5.995 2 65.21 0.183 5 Fe-CeO2@TiO2 95.33 0.121 2 5.084 6 68.54 0.177 7 Cu-CeO2@TiO2 113.00 0.161 4 5.711 6 66.20 0.190 2 
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[1] HU H, CAI S X, LIH R. Mechanistic aspects of deNOx processing over TiO2 supported Co-Mn oxide catalysts:Structure-activity relationships and in situ RIFTs analysis[J]. ACS Catal, 2015, 5(10):6069-6077. doi: 10.1021/acscatal.5b01039 [2] LU X N, SONG C Y, CHANG C C. Manganese oxides supported on TiO2-GR nanocomposite catalysts for selective catalytic reduction of NOx with NH3 at low temperature[J]. Ind Eng Chem Res, 2014, 53(29), 11601-11610. doi: 10.1021/ie5016969 [3] 张光学, 周安琪, 范海燕, 王进卿, 池作和.铁铈氧化物SCR脱硝催化剂的制备及性能[J].燃料化学学报, 2015, 43(10):1267-1272. http://rlhxxb.sxicc.ac.cn/CN/abstract/abstract18718.shtmlZHANG Guang-xue, ZHOU An-qi, FAN Hai-yan, WANG Jin-qing, CHI Zuo-he. Preparation of Fe-Ce oxide SCR denitration catalyst and its performance study[J]. J Fuel Chem Technol, 2015, 43(10):1267-1272. http://rlhxxb.sxicc.ac.cn/CN/abstract/abstract18718.shtml [4] 朱斌, 费兆阳, 陈献, 汤吉海, 崔咪芬, 乔旭. Al-PILC负载铜铁复合氧化物在NH3选择性催化还原NO中的协同作用[J].燃料化学学报, 2014, 42(9):1102-1110. http://rlhxxb.sxicc.ac.cn/CN/abstract/abstract18490.shtmlZHU Bin, FEI Zhao-yang, CHEN Xian, TANG Ji-hai, CUI Mi-fen, QIAO Xu. Synergetic effect of Cu-Fe composite oxides supported on Al-PILC for SCR of NO with NH3[J]. J Fuel Chem Technol, 2014, 42(9):1102-1110. http://rlhxxb.sxicc.ac.cn/CN/abstract/abstract18490.shtml [5] TANG F, XU B, SHI H. The poisoning effect of Na+ and Ca2+ ions doped on the V2O5/TiO2 catalysts for selective catalytic reduction of NO by NH3[J]. Appl Catal B:Environ, 2010, 94(2):71-76. https://www.researchgate.net/publication/223451483_The_poisoning_effect_of_Na_and_Ca2_ions_doped_on_the_V2O5TiO2_catalysts_for_selective_catalytic_reduction_of_NO_by_NH3 [6] YANG J, YANG Q, SUN J, LIU Q C, ZHAO D. Effects of mercury oxidation on V2O5-WO3/TiO2 catalyst properties in NH3-SCR process[J].Catal Commun, 2015, 59:147-156. https://www.researchgate.net/publication/267100551_Effects_of_mercury_oxidation_on_V2O5-WO3TiO2_catalyst_properties_in_NH3-SCR_process [7] PAPPAS D K, BONINGARI T, BOOLCHAND P, SMIRNIOTIS P G. Novel manganese oxide confined interweaved titania nanotubes for the low-temperature selective catalytic reduction (SCR) of NOx by NH3[J]. J Catal, 2016, 334:1-13. doi: 10.1016/j.jcat.2015.11.013 [8] YAO W, LIU Y, WANG X, WENG X, ZHANG H, WU Z. The superior performance of sol-gel made Ce-O-P catalyst for selective catalytic reduction of NO with NH3[J]. J Phys Chem C, 2016, 120(1):221-229. doi: 10.1021/acs.jpcc.5b07734 [9] CHANG H, WU Q, ZHANG T, LI M, SUN X, LI J, DUAN L, HAO J. Design strategies for CeO2-MoO3 catalysts for de NOx and Hg0 oxidation in the presence of HCl:the significance of the surface acid-base properties[J]. Environ Sci Technol, 2015, 49(20):12388-12394. doi: 10.1021/acs.est.5b02520 [10] 刘俊, 王亮亮, 费兆阳, 陈献, 汤吉海, 崔咪芬, 乔旭.非晶态CeO2@TiO2催化剂的结构、性质及其选择催化还原脱硝性能[J].燃料化学学报, 2016, 44(8):954-960. doi: 10.1016/S1872-5813(16)30043-3LIU Jun, WANG Liang-liang, FEI Zhao-yang, CHEN Xian, TANG Ji-hai, CUI Mi-fen, QIAO Xu. Structure and properties of amorphous CeO2@TiO2catalyst and its performance in the selective catalytic reduction of NO with NH3[J]. J Fuel Chem Technol, 2016, 44(8):954-960. doi: 10.1016/S1872-5813(16)30043-3 [11] LI Y, WAN Y, LI Y P, ZHAN S H, GUAN Q X, TIAN Y. Low-temperature selective catalytic reduction of NO with NH3 over Mn2O3-doped Fe2O3hexagonal microsheets[J]. ACS Appl Mater Interfaces, 2016, 8(8):5224-5233. doi: 10.1021/acsami.5b10264 [12] HAN J, MEEPRASERT J, MAITARAD P. Investigation of the facet-dependent catalytic performance of Fe2O3/CeO2 for the selective catalytic reduction of NO with NH3[J]. J Phys Chem C, 2016, 120(3):1523-1533. doi: 10.1021/acs.jpcc.5b09834 [13] HU H, CAI S, LI H. Mechanistic aspects of de NOx processing over TiO2 supported Co-Mn oxide catalysts:Structure-activity relationships and in situ DRIFTs analysis[J]. Acs Catal, 2015, 5(10):6069-6077. doi: 10.1021/acscatal.5b01039 [14] 徐希化, 费兆阳, 陈献, 汤吉海, 崔咪芬, 乔旭.气凝胶骨架镶嵌的CeO2纳米团簇催化氧化HCl制Cl2[J].化工学报, 2015, 66(9):3421-3427. http://www.cqvip.com/QK/90316X/201509/665818473.htmlXU Xi-hua, FEI Zhao-yang, CHEN Xian, TANG Ji-hai, CUI Mi-fen, QIAO Xu. CeO2nanoclusters stabilized in aerogel matrix as catalysts for Cl2 production from HCl oxidation[J]. CIESC J, 2015, 66(9):3421-3427. http://www.cqvip.com/QK/90316X/201509/665818473.html [15] ARAMEDNDIA M A, BORAU V, JIMENEZ C. Synthesis and characterization of ZrO2 as an acid-base catalyst dehydration-dehydrogenation of propan-2-ol[J]. J Chem Soc, 1997, 93(7):1431-1438. http://www.academia.edu/8089508/Synthesis_and_characterization_of_ZrO2_as_an_acid_base_catalyst_Dehydration_dehydrogenation_of_propan-2-ol [16] CASAPU M, KROCHER O, MEHRING M, NACHTEGAAL M, BORCA C. Characterization of nb-containing MnOx-CeO2catalyst for low-temperature selective catalytic reduction of NO with NH3[J]. J Phys Chem C, 2010, 114(21):9791-9801. doi: 10.1021/jp911861q [17] YANG S, XIONG S, LIAO Y, XIAO X, QI F, PENG Y, FU Y, SHAN W, LI J. Mechanism of N2O formation during the low-temperature selective catalytic reduction of NO with NH3 over Mn-Fe spinel[J]. Environ Sci Technol, 2015, 5(4):10354-10362. https://www.researchgate.net/publication/264644226_Mechanism_of_N2O_Formation_during_the_Low-Temperature_Selective_Catalytic_Reduction_of_NO_with_NH3_over_Mn-Fe_Spinel [18] GIRAUD F, GEANTET C, GUILHAUME N, GROS S, PORCHERON L, KANNICHE M, BIANCHI D. Experimental microkinetic approach of de-NOx by NH3on V2O5/WO3/TiO2 catalysts.1.Individual heats of adsorption of adsorbed NH3 species on a sulfate-free TiO2 support using adsorption isobars[J]. J Phys Chem C, 2014, 118(29):15664-15676. doi: 10.1021/jp502582g [19] BONINGARI A S T, SMIRNIOTIS P. Nickel-doped Mn/TiO2 as an efficient catalyst for low temperature SCR of NO with NH3:Catalytic evaluation and characterizations[J]. J Catal, 2012, 288(4):74-83. https://www.researchgate.net/publication/256737926_Nickel-doped_MnTiO2_as_an_efficient_catalyst_for_the_low-temperature_SCR_of_NO_with_NH3_Catalytic_evaluation_and_characterizations [20] ZHANG L, LIL L, CAOY, YAOX J, GECH Y, GAO F. Getting insight into the influence of SO2on TiO2/CeO2for the selective catalytic reduction of NO by NH3[J]. Appl Catal B:Environ, 2015, 165(18):589-598. [21] JINR B, LIU Y, WANG Y, WANG L C, WU ZH B, WANG H Q, WENG X L. The role of cerium in the improved SO2 tolerance for NO reduction with NH3over Mn-Ce/TiO2catalyst at low temperature[J]. Appl Catal B:Environ, 2014, 148-149(4):582-588. https://www.researchgate.net/publication/273533509_The_role_of_cerium_in_the_improved_SO2_tolerance_for_NO_reduction_with_NH3_over_Mn-CeTiO2_catalyst_at_low_temperature [22] LIU Z M, YI Y, LIJ H, SEONGI W, WANGB Y, CAOX Z, LIZ X. A superior catalyst with dual redox cycles for the selective reduction of NOx by ammonia[J]. Chem Commun, 2013, 49(70):7726-7728. doi: 10.1039/c3cc43041c [23] PADMANABHA R E, NEERAJA E, THIRUPATHI B, ROBERT P, PANAGIOITS G S. Investigation of the selective catalytic reduction of nitric oxide with ammonia over Mn/TiO2catalysts through transient isotopic labeling and in situ FT-IR studies[J]. J Catal, 2012, 292(4):53-63. https://www.researchgate.net/publication/256737760_Investigation_of_the_selective_catalytic_reduction_of_nitric_oxide_with_ammonia_over_MnTiO2_catalysts_through_transient_isotopic_labeling_and_in_situ_FT-IR_studies -
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