Sn、Ti掺杂改性γ-Fe2O3催化剂结构及NH3-SCR脱硝活性研究

王栋; 吴惊坤; 牛胜利; 路春美; 徐丽婷; 于贺伟; 李婧

Sn、Ti掺杂改性γ-Fe₂O₃催化剂结构及NH₃-SCR脱硝活性研究

王栋^1,2,
吴惊坤¹,
牛胜利^1,2,
路春美^1,2,,
徐丽婷^1,2,
于贺伟¹,
李婧³

1.
山东大学能源与动力工程学院, 山东济南 250061;
2.
山东大学燃煤污染物减排国家工程实验室, 山东济南 250061;
3.
山东大学化学与化工学院, 山东济南 250100

基金项目: 国家自然科学基金(51276101); 高等学校博士学科点专项科研基金(20120131110022); 山东大学基本科研业务费专项资金(2015JC024)。

详细信息

通讯作者:
路春美

中图分类号: X511
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出版历程
- 收稿日期: 2015-05-10
- 修回日期: 2015-06-26
- 刊出日期: 2015-07-30

Structural property of γ-Fe₂O₃ catalysts doped with Sn and Ti and their activity in the selective catalytic reduction of NO_x

1.
School of Energy and Power Engineering, Shandong University, Jinan 250061, China;
2.
National Engineering Laboratory for Coal-Burning Pollutants Emission Reduction, Shandong University, Jinan 250061, China;
3.
School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China

摘要

摘要: 采用共沉淀-微波热解法,制备一系列Sn、Ti掺杂改性γ-Fe₂O₃催化剂样品(γ-Fe_0.95Ti_0.05O_z、γ-Fe_0.95Sn_0.05O_z、γ-Fe_0.95Sn_0.025Ti_0.025O_z),研究Sn、Ti掺杂对γ-Fe₂O₃催化剂SCR脱硝活性的影响,借助XRD、N₂吸附-脱附、EDS及SEM等手段对催化剂晶相、孔结构、表面元素及微观形貌等进行表征分析。结果表明,Sn、Ti掺杂后以无定形态高度分散于γ-Fe₂O₃晶格中,与Fe形成固溶体;单一助剂Ti掺杂制得的γ-Fe_0.95Ti_0.05O_z 最高脱硝效率达98.3%,且在250~400 ℃脱硝效率保持90%以上;Ti掺杂可以细化γ-Fe₂O₃晶粒,优化2~100 nm孔径孔隙结构,抑制α-Fe₂O₃的生成,促使γ-Fe₂O₃形成细致、均匀、独立的球状颗粒,对SCR反应有利;Sn掺杂则使催化剂出现严重烧结现象,导致2~6 nm孔径孔结构贫乏,对SCR脱硝反应不利;在Sn、Ti协同作用下,催化剂表面氧铁原子物质的量比由1.83降至1.33,表面晶格氧显著下降,一定程度上限制了SCR反应速率的提高。
- 选择性催化还原 /
- 脱硝 /
- 催化剂 /
- γ-Fe₂O₃ /
- 助剂掺杂
Abstract: A series of γ-Fe₂O₃ catalysts doped with Sn and Ti (γ-Fe_0.95Ti_0.05O_z, γ-Fe_0.95Sn_0.05O_z, and γ-Fe_0.95Sn_0.025Ti_0.025O_z) were prepared by the microwave assisted co-precipitation method. The crystal phase, pore structure, surface element distribution and microscopic morphology of the doped γ-Fe₂O₃ catalysts were characterized by X-ray diffraction (XRD), N₂ sorption, energy dispersive spectrometer (EDS) and scanning electron microscope (SEM); the influence of Sn and Ti doping on their activity in the selective catalytic reduction (SCR) of NO_x was investigated. The results indicated that Sn and Ti are highly dispersed as amorphous species in crystal lattice of γ-Fe₂O₃, forming sosoloid with Fe. Through doping with Ti, the γ-Fe_0.95Ti_0.05O_z catalyst exhibits a high de-NO_x efficiency of above 90% at 250~400 ℃, with a maximum of 98.3%; the addition of Ti is effective to reduce the crystallization degree of γ-Fe₂O₃, improve the pore structure of 2~100 nm, and suppress the formation of α-Fe₂O₃ phase, which are of benefits to get tiny and uniform discrete γ-Fe₂O₃ particles with high activity in SCR. However, Sn as an additive may aggravate the sintering and derogate pore structure of 2~6 nm for the γ-Fe_0.95Sn_0.05O_z catalyst, which is detrimental to SCR. The incorporation of both Sn and Ti leads to a decrease of the surface O/Fe atomic ratio from 1.83 to 1.33; the dramatic decrease of surface lattice oxygen content due to the synergistic effect between Sn and Ti may restrain the SCR activity of γ-Fe_0.95Sn_0.025Ti_0.025O_z.
- selective catalytic reduction (SCR) /
- de-NO_x /
- catalyst /
- γ-Fe₂O₃ /
- additives doped

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参考文献(28)

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