WO3改性CeO2-TiO2催化剂的低温NH3-NO/NO2 SCR活性和机理研究

引用本文: 陈磊, 翁鼎, 汪家道, 翁端, 曹丽. WO₃改性CeO₂-TiO₂催化剂的低温NH₃-NO/NO₂ SCR活性和机理研究[J]. 催化学报, 2018, 39(11): 1804-1813. doi: 10.1016/S1872-2067(18)63129-8 shu

Citation: Lei Chen, Ding Weng, Jiadao Wang, Duan Weng, Li Cao. Low-temperature activity and mechanism of WO₃-modified CeO₂-TiO₂ catalyst under NH₃-NO/NO₂ SCR conditions[J]. Chinese Journal of Catalysis, 2018, 39(11): 1804-1813. doi: 10.1016/S1872-2067(18)63129-8 shu

WO₃改性CeO₂-TiO₂催化剂的低温NH₃-NO/NO₂ SCR活性和机理研究

陈磊 ^a, ,
翁鼎 ^a, ,
汪家道 ^a, ,
翁端 ^b, ,
曹丽 ^b,

a 清华大学机械工程学院摩擦学国家重点实验室, 北京 100084;
b 清华大学材料学院先进材料教育部重点实验室, 北京 100084
基金项目:
国家自然科学基金（51775296，51375253）.

摘要: 在铈钛基NH₃-SCR催化材料中，改性元素对催化材料的酸性位和氧化还原性能的影响较大。本文采用过量浸渍法分别制备了CeO₂-TiO₂（CeTi）和CeO₂/WO₃-TiO₂（CeWTi）催化剂，研究了CeWTi催化材料结构、酸性位及氧化还原性能对NH₃-NO/NO₂ SCR反应性能的影响.结果发现，CeTi和CeWTi样品均有较优异的NH₃-NO/NO₂ SCR催化性能，后者略高.WO₃的加入增加了催化材料的表面酸性，对其氧化还原性能影响不大.通过对反应中间物种NH₄NO₃的研究，发现NH₄NO₃的分解主要与氧化还原性能相关，而NO还原NH₄NO₃的反应需要氧化还原能力和酸性位共同作用，即在氧化还原性能差异不大的条件下，酸性对该反应起到重要作用.而该反应也是NH₃-NO/NO₂ SCR的限速步骤，这是CeWTi催化材料活性高于CeTi催化材料的原因.
同时，为了获得NH₃-NO/NO₂ SCR反应的高活性，NO₂：NO比例宜为1：1.然而现实情况中，预氧化催化材料的氧化活性、NO_x浓度、温度等变量使得准确控制NO₂的比例较难，因此，深入了解NO₂浓度对NH₃-NO/NO₂ SCR反应的影响至关重要.本文探讨NO₂：NO的比例、O₂浓度等对NH₃-NO/NO₂ SCR反应性能的影响；并研究了不同NO₂含量条件下NH₃-NO/NO₂ SCR反应网络.通过分析CeWTi材料上NH₃-NO/NO₂ SCR反应网络可知，当NO与NO₂比例为1：1时，NH₃-SCR催化活性最高，并以快速SCR形式进行；当NO与NO₂比例为1：1消耗完全之后，剩余的NO或NO₂各自独立以标准或慢速SCR进行，不影响其本来的反应活性.催化材料的标准SCR、快速SCR和慢速SCR均取决于材料表面酸度和氧化还原性能，但快速SCR和慢速SCR对材料这两方面性能的要求相对较低.同时O₂并不参与快速和慢速SCR，而NO₂可以取代O₂作为SCR反应中主要的氧化剂，氧化Ce⁴⁺为Ce³⁺，甚至比O₂和NO再氧化活性位的能力更强，保持催化材料的高催化活性.低温条件时，慢速SCR和快速SCR反应均在材料表面生成硝酸铵中间物种，但由于慢速SCR气氛中缺乏NO将硝酸铵还原，进而引发快速SCR反应，因此材料表面快速SCR的NO_x转化率要高于慢速SCR反应；高温条件下，由于硝酸铵容易热分解，导致硝酸铵的抑制效应不太明显.NH₄NO₃分解是NO₂含量升高后N₂O的形成的主要途径.

关键词:

English

Low-temperature activity and mechanism of WO₃-modified CeO₂-TiO₂ catalyst under NH₃-NO/NO₂ SCR conditions

a State Key Laboratory of Tribology, School of Mechanical Engineering, Tsinghua University, Beijing 100084, China;
b Key Laboratory of Advanced Materials of Ministry of Education, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
Received Date: 05 May 2018
Revised Date: 22 June 2018
Fund Project:
This work was supported by the National Natural Science Foundation of China (51775296, 51375253).

Abstract: The CeO₂-TiO₂ (CeTi) and CeO₂/WO₃-TiO₂ (CeWTi) catalysts were prepared by a sol-gel precipitation method and their NH₃-NO/NO₂ selective catalytic reduction (SCR) performance was studied. N₂O formation and effect of oxygen concentration on SCR performance over CeWTi catalyst were also investigated while varying the NO₂/NO_x ratio. Results indicate that fast SCR behavior of CeWTi catalyst has the best NH₃-NO/NO₂ SCR performance due to the catalyst reoxidation rate by NO₂ higher than by O₂. Compared with CeTi catalyst, CeWTi catalyst exhibits higher de-NO_x performance under NH₃-NO/NO₂ SCR conditions. As the CeTi and CeWTi catalysts exhibit similar redox property, addition of WO₃ provides more acid sites which accelerate the reaction between NH₄NO₃ and NO to get a superior low-temperature activity. Amount of N₂O formation shows a peak at 250℃ mainly derived from NH₄NO₃ decomposition.

Key words:

1. [1] B. Zhao, R. Ran, X. Guo, L. Cao, T. Xu, Z. Chen, X. Wu, Z. Si, D. Weng, Appl. Catal. A, 2017, 545, 64-71.
2. [2] J. Yu, Z. Si, L. Chen, X. Wu, D. Weng, Appl. Catal. B, 2015, 163, 223-232.
3. [3] K. Skalska, J. S. Miller, S. Ledakowicz, Sci. Total Environ., 2010, 408, 3976-3989.
4. [4] W. Cai, Q. Zhong, D. Wang, Y. Zhao, M. Chen, Y. Bu, ACS Appl. Nano Mater., 2018, 1, 1150-1163.
5. [5] Z. Duan, J. Liu, J. Shi, Z. Zhao, Y. Wei, X. Zhang, G. Jiang, A. Duan, J. Environ. Sci., 2018, 65, 1-7.
6. [6] Z. Si, D. Weng, X. Wu, J. Yang, B. Wang, Catal. Commun., 2010, 11, 1045-1048.
7. [7] M. Fu, C. Li, P. Lu, L. Qu, M. Zhang, Y. Zhou, M. Yu, Y. Fang, Catal. Sci. Technol., 2014, 4, 14-25.
8. [8] L. Zhu, Y. Zeng, J. Deng, S. Zhang, Q. Zhong, J. Environ. Sci., 2017, 54, 277-287.
9. [9] A. Grossale, I. Nova, E. Tronconi, D. Chatterjee, M. Weibel, J. Catal., 2008, 256, 312-322.
10. [10] M. Iwasaki, H. Shinjoh, Appl. Catal. A, 2010, 390, 71-77.
11. [11] M. Bendrich, A. Scheuer, R. E. Hayes, M. Votsmeier, Appl. Catal. B, 2018, 222, 76-87.
12. [12] L. Chen, Z. Wu, Z. Si, D. Weng, X. Wu, J. Environ. Sci., 2015, 31, 240-247.
13. [13] M. Koebel, M. Elsener, G. Madia, Ind. Eng. Chem. Res., 2001, 40, 52-59.
14. [14] C. Ciardelli, I. Nova, E. Tronconi, D. Chatterjee, T. Burkhardt, M. Weibel, Chem. Eng. Sci., 2007, 62, 5001-5006.
15. [15] I. Nova, C. Ciardelli, E. Tronconi, D. Chatterjee, M. Weibel, Top. Catal., 2007, 42-43, 43-46.
16. [16] C. Ciardelli, I. Nova, E. Tronconi, D. Chatterjee, B. Bandl-Konrad, M. Weibel, B. Krutzsch, Appl. Catal. B, 2007, 70, 80-90.
17. [17] E. Tronconi, I. Nova, C. Ciardelli, D. Chatterjee, M. Weibel, J. Catal., 2007, 245, 1-10.
18. [18] R. P. Vélez, U. Bentrup, W. Grünert, A. Brückner, Top. Catal., 2017, 60, 1641-1652.
19. [19] M. Schwidder, S. Heikens, A. De Toni, S. Geisler, M. Berndt, A. Bruckner, W. Grunert, J. Catal., 2008, 259, 96-103.
20. [20] M. Colombo, I. Nova, E. Tronconi, Catal. Today, 2012, 197, 243-255.
21. [21] L. Chen, J. Li, M. Ge, L. Ma, H. Chang, Chin. J. Catal., 2011, 32, 836-841.
22. [22] Q. Li, H. Gu, P. Li, Y. Zhou, Y. Liu, Z. Qi, Y. Xin, Z. Zhang, Chin. J. Catal., 2014, 35, 1289-1298.
23. [23] W. Xu, Y. Yu, C. Zhang, H. He, Catal. Commun., 2008, 9, 1453-1457.
24. [24] L. Chen, J. Li, M. Ge, R. Zhu, Catal. Today, 2010, 153, 77-83.
25. [25] S. Zhang, Q. Zhong, Y. Shen, L. Zhu, J. Ding, J. Colloid Interfaces Sci., 2015, 448, 417-426.
26. [26] L. Cao, L. Chen, X. Wu, R. Ran, T. Xu, Z. Chen, D. Weng, Appl. Catal. A, 2018, 557, 46-54.
27. [27] Z. Ma, D. Weng, X. Wu, Z. Si, B. Wang, Catal. Commun., 2012, 27, 97-100.
28. [28] L. Chen, D. Weng, Z. Si, X. Wu, Prog. Nat. Sci-Mater., 2012, 22, 265-272.
29. [29] Z. Ma, D. Weng, X. Wu, Z. Si, J. Environ. Sci., 2012, 24, 1305-1316.
30. [30] L. Chen, Z. Si, X. Wu, D. Weng, ACS Appl. Mater. Interfaces, 2014, 6, 8134-8145.
31. [31] L. Li, L. Zhang, K. Ma, W. Zou, Y. Cao, Y. Xiong, C. Tang, L. Dong, Appl. Catal. B, 2017, 207, 366-375.
32. [32] W. Shan, F. Liu, H. He, X. Shi, C. Zhang, Appl. Catal. B, 2012, 115-116, 100-106.
33. [33] S. Yang, Y. Guo, H. Chang, L. Ma, Y. Peng, Z. Qu, N. Yan, C. Wang, J. Li, Appl. Catal. B, 2013, 136-137, 19-28.
34. [34] W. D. Halstead, J. Appl. Chem., 1970, 20, 129-132.
35. [35] X. Wu, Z. Zhou, D. Weng, B. Wang, J. Environ. Sci., 2012, 24, 458-463.
36. [36] L. Zhang, J. Sun, Y. Xiong, X. Zeng, C. Tang, L. Dong, Chin. J. Catal., 2017, 38, 1749-1758.
37. [37] A. Savara, M. J. Li, W. M. H. Sachtler, E. Weitz, Appl. Catal. B, 2008, 81, 251-257.
38. [38] Z. Chen, Z. Si, L. Cao, X. Wu, R. Ran, D. Weng, Catal. Sci. Technol., 2017, 7, 2531-2541.
39. [39] Z. Ma, X. Wu, H. Härelind, D. Weng, B. Wang, Z. Si, J. Mol. Catal. A, 2016, 423, 172-180.
40. [40] K. Liu, F. Liu, L. Xie, W. Shan, H. He, Catal. Sci. Technol., 2015, 5, 2290-2299.
41. [41] X. Xiao, S. Xiong, Y. Shi, W. Shan, S. Yang, J. Phys. Chem. C, 2016, 120, 1066-1076.
42. [42] M. P. Ruggeri, A. Grossale, I. Nova, E. Tronconi, H. Jirglova, Z. Sobalik, Catal. Today, 2012, 184, 107-114.
43. [43] M. P. Ruggeri, T. Selleri, M. Colombo, I. Nova, E. Tronconi, J. Catal., 2015, 328, 258-269.
44. [44] A. Grossale, I. Nova, E. Tronconi, J. Catal., 2009, 265, 141-147.
45. [45] M. P. Ruggeri, J. Luo, I. Nova, E. Tronconi, K. Kamasamudram, A. Yezerets, Catal. Today, 2018, 307, 48-54.
46. [46] M. Colombo, I. Nova, E. Tronconi, V. Schmeißer, B. Bandl-Konrad, L. Zimmermann, Appl. Catal. B, 2012, 111-112, 106-118.
47. [47] X. Shi, F. Liu, L. Xie, W. Shan, H. He, Environ. Sci. Technol., 2013, 47, 3293-3298.
48. [48] M. Koebel, G. Madia, F. Raimondi, A. Wokaun, J. Catal., 2002, 209, 159-165.
49. [49] S. S. Kim, S. H. Choi, S. C. Hong, Environ. Eng. Sci., 2010, 27, 845-852.
50. [50] I. Nova, C. Ciardelli, E. Tronconi, D. Chatterjee, B. Bandl-Konrad, Catal. Today, 2006, 114, 3-12.
51. [51] C. Ciardelli, I. Nova, E. Tronconi, D. Chatterjee, B. Bandl-Konrad, Chem. Commun., 2004, 2718-2719.

扫一扫看文章

计量

PDF下载量: 4
文章访问数: 1350
HTML全文浏览量: 136

通讯作者: 陈斌, bchen63@163.com

1.
沈阳化工大学材料科学与工程学院沈阳 110142

WO₃改性CeO₂-TiO₂催化剂的低温NH₃-NO/NO₂ SCR活性和机理研究

English

Low-temperature activity and mechanism of WO₃-modified CeO₂-TiO₂ catalyst under NH₃-NO/NO₂ SCR conditions

CCS Chemistry：嵌段共聚物自组装成 “三明治”二维有机材料，实现纳米级压力传感功能

CCS Chemistry：颜徐州、鲍哲南：你的皮肤可能是一片SPMs

CCS Chemistry：工作高效不疲劳，只须让催化剂动起来

CCS Chemistry：静电组装导向聚合- 聚电解质纳米凝胶量化制备新策略

CCS Chemistry：金黄色葡萄球菌醛基脱氢酶是如何识别特异性底物的？

计量

通讯作者: 陈斌, bchen63@163.com

中国化学会秘书处