Nd掺杂V_2O_5/TiO_2低温NH_3选择性催化还原NO_x性能研究
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摘要
采用溶胶凝胶法和浸渍法制备了Nd掺杂V_2O_5/TiO_2催化剂.用XRD和Raman技术对其晶相结构和分散性进行了表征,并在固定床反应器上评价了其催化活性.然后考察了煅烧温度对催化剂脱硝性能的影响,结合XRD表征结果可知煅烧温度没有改变TiO_2的晶型,只影响了其结晶度.同时氮气吸脱附表征及BET计算结果显示350℃煅烧时催化剂比表面积最大.研究了O_2浓度以及氨氮比对催化剂脱硝性能的影响.同时考察了Nd掺杂催化剂的稳定性,发现Nd改性催化剂有较好的稳定性.并对Nd掺杂催化剂做了抗硫抗水考察,研究结果表明, Nd掺杂催化剂有较好的耐硫耐水性.
The Nd-doped V_2O_5/TiO_2 catalysts were prepared by sol-gel method and impregnation method. The crystal structure and dispersibility of the catalysts were characterized by XRD and Raman techniques, and their catalytic activities were evaluated on a fixed bed reactor. The effect of calcination temperature on the denitration performance of the catalyst was investigated. According to the XRD characterization results, the calcination temperature did not change the crystal form of TiO_2, which only affected its crystallinity. Meanwhile, the N_2 adsorption-desorption cha-racterization and BET results showed that the specific surface area is the largest when calcined at 350℃. Then the effects of O_2 concentration and ammonia-nitrogen ratio on the denitration performance of the catalyst were studied. At the same time, the stability of Nd-doped catalyst was investigated. It was found that Nd modified catalyst has good stability. The sulfur and water-resistance of Nd-doped catalysts were investigated. The results showed that the Nd-doped catalysts have good sulfur and water resistance.
The Nd-doped V_2O_5/TiO_2 catalysts were prepared by sol-gel method and impregnation method. The crystal structure and dispersibility of the catalysts were characterized by XRD and Raman techniques, and their catalytic activities were evaluated on a fixed bed reactor. The effect of calcination temperature on the denitration performance of the catalyst was investigated. According to the XRD characterization results, the calcination temperature did not change the crystal form of TiO_2, which only affected its crystallinity. Meanwhile, the N_2 adsorption-desorption cha-racterization and BET results showed that the specific surface area is the largest when calcined at 350℃. Then the effects of O_2 concentration and ammonia-nitrogen ratio on the denitration performance of the catalyst were studied. At the same time, the stability of Nd-doped catalyst was investigated. It was found that Nd modified catalyst has good stability. The sulfur and water-resistance of Nd-doped catalysts were investigated. The results showed that the Nd-doped catalysts have good sulfur and water resistance.
引文
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[27] Xu W, Wang H, Zhou X, et al. CuO/TiO2 catalysts for gas-phase Hg0 catalytic oxidation[J]. Chem Enginee J, 2014, 243: 380-385.
[28] Zhang X, Li C, Zhao L, et al. Simultaneous removal of elemental mercury and NO from flue gas by V2O5-CeO2/TiO2 catalysts[J]. Appl Surf Sci, 2015, 347: 392-400.
[29] Koebel M, Elsener A M, Madia G. Reaction pathways in the selective catalytic reduction process with NO and NO2 at low temperatures[J]. Indus & Engineer Chem Res, 2001, 40(1): 52-59.
[30] Wang X, Gui K. Fe2O3 particles as superior catalysts for low temperature selective catalytic reduction of NO with NH3[J]. J Environ Sci, 2013, 25(12): 2469-2475.
[31] Kijlstra W S, Biervliet M, Poels E K, et al. Deactivation by SO2 of MnOx/Al2O3 catalysts used for the selective catalytic reduction of NO with NH3 at low temperatures[J]. Appl Catal B Environ, 1998, 16(4): 327-337.
[32] Lee S M, Park K H, Hong S C, et al. MnOx/CeO2-TiO2 mixed oxide catalysts for the selective catalytic reduction of NO with NH3 at low temperature[J]. Chem Engineer J, 2012, 195/196: 323-331.
[33] Li Y, Li Y, Wan Y, et al. Structure-performance relationships of MnO2 nanocatalyst for the low-temperature SCR removal of NOx under ammonia[J]. Rsc Adv, 2016, 6(60): 54926-54937.
[2] a. Ma T, Takeuchi K. Technology choice for reducing NOx math container loading mathjax emissions: An empi- rical study of chinese power plants[J]. Ener Pol, 2017, 102: 362-376.b. Jin Qi-jie(金奇杰), Sui Guo-rong(眭国荣), Liu Qing(刘青), et al. Compatibility optimization of Mn-Mo-W-Ox catalyst for selective catalytic reduction of NO by NH3(Mn-Mo-W-Ox脱硝催化剂活性组分的配伍优化) [J]. J Mol Catal(China)(分子催化), 2017, 31(2): 159-168.c. Chen Meng-yin(陈梦寅), Zhao Meng-meng(赵梦梦), Yu Hai-tao(余海涛), et al. Effect of TiO2 modulation by SnO2 on the structure and SCR performance of V2O5-WO3/TiO2 catalysts SnO2改性TiO2对V2O5-WO3/TiO2催化剂结构和SCR 性能影响) [J]. J Mol Catal(China)(分子催化), 2017, 31(1): 61-73.
[3] Liang Z, Ma X, Lin H, et al. The energy consumption and environmental impacts of SCR technology in China[J]. Appl Ener, 2011, 88(4): 1120-1129.
[4] Koebel M, Elsener M, Kleemann M. Urea-SCR: A pro- mising technique to reduce NOx emissions from automotive diesel engines[J]. Catal Today, 2000, 59(3): 335-345.
[5] Liu J, Li X, Zhao Q, et al. Mechanistic investigation of the enhanced NH3-SCR on cobalt-decorated Ce-Ti mixed oxide: In situ FTIR analysis for structure-activity correlation[J]. Appl Catal B: Environ, 2017, 200: 297-308.
[6] Peng Y, Li J, Huang X, et al. Deactivation mechanism of potassium on the V2O5/CeO2 catalysts for SCR reaction: acidity, reducibility and adsorbed-NOx[J]. Environ Sci & Technol, 2014, 48(8): 4515-4520.
[7] Xiaodong W U, Wenchao Y U, Zhichun S I, et al. Chemical deactivation of V2O5-WO3/TiO2 SCR catalyst by combined effect of potassium and chloride[J]. Fron Environ Sci & Engineer, 2013, 7(3): 420-427.
[8] Zhang S, Zhong Q, Zhao W, et al. Surface characterization studies on F-doped V2O5/TiO2 catalyst for NO reduction with NH3 at low-temperature[J]. Chem Engineer J, 2014, 253: 207-216.
[9] Zhu L, Zhong Z, Xue J, et al. NH3-SCR performance and the resistance to SO2 for Nb doped vanadium based catalyst at low temperatures[J]. J Environ Sci (China), 2018, 65: 306-316.
[10] Hu G, Yang J , Tian Y , et al. Effect of Ce doping on the resistance of Na over V2O5-WO3/TiO2 SCR catalysts[J]. Mater Res Bull, 2018, 104: 112-118.
[11] Sun D, Wang K, Xu Z, et al. Synthesis and photocatalytic activity of sulfate modified Nd-doped TiO2 under visible light irradiation[J]. J Rare Eart, 2015, 33(5): 491-497.
[12] Bokare A, Pai M , Athawale A A. Surface modified Nd doped TiO2 nanoparticles as photocatalysts in UV and solar light irradiation[J]. Sol Ener, 2013, 91: 111-119.
[13] Du J, Gu X, Wu Q, et al. Hydrophilic and photocataly- tic activities of Nd-doped titanium dioxide thin films[J]. Transac Nonf Meta Soc Chin, 2015, 25(8): 2601-2607.
[14] Parnicka P, Mazierski P, Grzyb T, et al. Preparation and photocatalytic activity of Nd-modified TiO2, photoca- talysts: Insight into the excitation mechanism under visible light[J]. J Catal, 2017, 353: 211-222.
[15] Zhao L, Li C, Zhang J, et al. Promotional effect of CeO2 modified support on V2O5-WO3/TiO2 catalyst for elemental mercury oxidation in simulated coal-fired flue gas[J]. Fuel, 2015, 153: 361-369.
[16] Zhu Y, Zhang Y, Xiao R, et al. Novel holmium-modified Fe-Mn/TiO2 catalysts with a broad temperature window and high sulfur dioxide tolerance for low-temperature SCR[J]. Catal Commun, 2017, 88: 64-67.
[17] Guo R T, Sun X, Liu J, et al. Enhancement of the NH3-SCR catalytic activity of MnTiOx, catalyst by the introduction of Sb[J]. Appl Catal A: Gener, 2018, 558: 1-8.
[18] Xie Z, Wang F, Liang J, et al. Enhanced catalytic efficiency of FeMnTiOx, SCR catalysts through adding tourmaline nanopowders during the one-step sol-gel process[J]. Mater Lett, 2018, 217: 60-63.
[19] Xin Qin(辛勤). Modern catalytic research method (现代催化研究方法) [M]. China: Science Press (中国: 科学出版社), 2009, 146.
[20] Liu J, Guo R T, Li M Y, et al. Enhancement of the SO2 resistance of Mn/TiO2 SCR catalyst by Eu modification: A mechanism study[J]. Fuel, 2018, 223: 385-393.
[21] Chen L, Li J, Ge M. Promotional Effect of Ce-doped V2O5-WO3/TiO2 with low vanadium loadings for selective catalytic reduction of NOx by NH3[J]. J Phys Chem C, 2009, 113(50): 21177-21184.
[22] Huang Y, Ho W , Ai Z , et al. Aerosol-assisted flow synthesis of B-doped, Ni-doped and B-Ni-codoped TiO2 solid and hollow microspheres for photocatalytic removal of NO[J]. Appl Catal B Environ, 2009, 89(3): 398-405.
[23] Zhao W, Zhong Q , Pan Y , et al. Systematic effects of S-doping on the activity of V2O5/TiO2 catalyst for low-temperature NH3-SCR[J]. Chem Engineer J, 2013, 228: 815-823.
[24] Kompio P G W A, Brückner, Angelika, et al. V2O5-WO3/TiO2 catalysts under thermal stress: Responses of structure and catalytic behavior in the selective catalytic reduction of NO by NH3[J]. Appl Catal B Environ, 2017, 217: 365-377.
[25] Gillot S, Dacquin J P, Dujardin C, et al. High intrinsic catalytic activity of CeVO4 -based catalysts for ammonia-SCR: Influence of pH during hydrothermal synthesis[J]. Top Catal, 2016, 59(10/12): 1-9.
[26] Zong L, Zhang G, Zhao H, et al. One pot synthesized CeO2-WO3-TiO2 catalysts with enriched TiO2 (001) facets for selective catalytic reduction of NO with NH3 by evaporation-induced self-assembly method[J]. Chem Engineer J, 2018, 354: 295-303.
[27] Xu W, Wang H, Zhou X, et al. CuO/TiO2 catalysts for gas-phase Hg0 catalytic oxidation[J]. Chem Enginee J, 2014, 243: 380-385.
[28] Zhang X, Li C, Zhao L, et al. Simultaneous removal of elemental mercury and NO from flue gas by V2O5-CeO2/TiO2 catalysts[J]. Appl Surf Sci, 2015, 347: 392-400.
[29] Koebel M, Elsener A M, Madia G. Reaction pathways in the selective catalytic reduction process with NO and NO2 at low temperatures[J]. Indus & Engineer Chem Res, 2001, 40(1): 52-59.
[30] Wang X, Gui K. Fe2O3 particles as superior catalysts for low temperature selective catalytic reduction of NO with NH3[J]. J Environ Sci, 2013, 25(12): 2469-2475.
[31] Kijlstra W S, Biervliet M, Poels E K, et al. Deactivation by SO2 of MnOx/Al2O3 catalysts used for the selective catalytic reduction of NO with NH3 at low temperatures[J]. Appl Catal B Environ, 1998, 16(4): 327-337.
[32] Lee S M, Park K H, Hong S C, et al. MnOx/CeO2-TiO2 mixed oxide catalysts for the selective catalytic reduction of NO with NH3 at low temperature[J]. Chem Engineer J, 2012, 195/196: 323-331.
[33] Li Y, Li Y, Wan Y, et al. Structure-performance relationships of MnO2 nanocatalyst for the low-temperature SCR removal of NOx under ammonia[J]. Rsc Adv, 2016, 6(60): 54926-54937.