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工程科学与技术:2021,53(4):233-239
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Ce改性锰酸镧催化剂的制备及脱硝性能研究
(1.四川大学 建筑与环境学院,四川 成都 610065;2.国家烟气脱硫工程技术研究中心,四川 成都 610065;3.四川大学 新能源与低碳技术研究院,四川 成都 610065)
Study on the Preparation and Denitration Performance of Ce Modified La-Mn Perovskite Catalyst
(1.College of Architecture and Environment, Sichuan Univ., Chengdu 610065, China;2.National Eng. Research Center for Flue Gas Desulfurization, Chengdu 610065, China;3.Inst. of New Energy and Low Carbon Technol., Sichuan Univ., Chengdu 610065, China)
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投稿时间:2020-12-20    修订日期:2021-03-16
中文摘要: 为了提高钙钛矿型锰酸镧的脱硝性能,采用柠檬酸溶胶-凝胶法一步合成一系列Ce改性的钙钛矿型La-Mn复合氧化物催化剂,并利用X射线衍射(XRD)、X射线光电子能谱(XPS)、扫描电镜(SEM)、N2吸脱附(BET)和程序升温技术(H2-TPR/NH3-TPD)表征方法对其结构、形貌、组成、表面物理化学性质等进行表征。活性测试结果表明:Ce改性后的钙钛矿型La-Mn复合氧化物催化剂的脱硝性能均得到了提升,当Ce∶Mn摩尔比为0.2时,催化剂具有最优异的脱硝活性,在135 ℃时可达到90%的NOx转化率,在135~260 ℃的温度窗口范围内保持90%以上的NOx转化率。XRD结果表明:Ce改性后的钙钛矿型La-Mn复合氧化物具有多孔结构并能保持LaMnO3.15的钙钛矿结构。然而,Ce离子并没有完全进入钙钛矿结构中,部分以氧化物的形式覆盖在催化剂表面,同时,导致晶格中部分Mn以Mn3O4的形式从钙钛矿结构中溢出,从而保持结构的稳定性和电荷平衡。SEM和BET结果表明:引入Ce后,催化剂的比表面积增加,提供更多的活性位点,促进脱硝反应的进行。XPS结果表明:Ce改性后的催化剂会产生更多的Mn4+以及化学吸附氧,促进了NO的氧化。程序升温技术结果表明:Ce改性后的催化剂具有更优异的氧化还原性能以及更多的酸性位点,有利于脱硝反应的进行。因此,Ce改性锰酸镧会通过促进NO的氧化和NH3的吸附来提高脱硝性能。
中文关键词: Ce改性  锰酸镧  脱硝
Abstract:In order to improve the denitration performance of La-Mn perovskite catalyst, a series of Ce modified perovskite La-Mn composite oxide catalysts were synthesized by citric acid sol-gel method. The structure, morphology, composition and surface physicochemical properties of the catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), N2 adsorption-desorption (BET) and temperature programmed technology (H2-TPR/NH3-TPD).The results of the activity test showed that the denitration performance of Ce modified perovskite type La-Mn composite oxide catalysts are improved. When the Ce/Mn molar ratio is 0.2, the catalyst has the best denitration activity. The NOx conversion rate could reach 90% at 135 ℃, and maintaining more than 90% NOx conversion in the temperature window range of 135~260℃. XRD results showed that the perovskite type La-Mn composite oxide modified by Ce has porous structure and could maintain the perovskite structure of LaMnO3.15. However, Ce ions do not completely enter the perovskite structure, and some of them cover the catalyst surface in the form of oxides. At the same time, part of Mn ions in the lattice overflow from the perovskite structure in the form of Mn3O4, thus maintaining the structural stability and charge balance. SEM and BET results showed that the specific surface area of the catalyst increases and more active sites are provided after the introduction of Ce, which promotes the denitration reaction. XPS results showed that Ce modified catalyst produces more Mn4+ and chemically adsorbed oxygen, which promotes the oxidation of NO. The results of temperature programmed technology showed that the catalyst modified by Ce has better redox performance and more acidic sites, which is conducive to the denitration reaction. Therefore, Ce modified La-Mn composite oxide could improve the denitration performance by promoting NO oxidation and NH3 adsorption.
文章编号:202001081     中图分类号:X53    文献标志码:
基金项目:国家自然科学基金面上项目(51878425);国家重点研发计划项目(2019YFC0214404)
作者简介:第一作者:郭家秀(1972-),女,副研究员.研究方向:大气污染控制.E-mail:guojiaxiu@scu.edu.cn
引用文本:
郭家秀,史雪珂,范爱东,李建军,楚英豪,袁山东.Ce改性锰酸镧催化剂的制备及脱硝性能研究[J].工程科学与技术,2021,53(4):233-239.
GUO Jiaxiu,SHI Xueke,FAN Aidong,LI Jianjun,CHU Yinghao,YUAN Shandong.Study on the Preparation and Denitration Performance of Ce Modified La-Mn Perovskite Catalyst[J].Advanced Engineering Sciences,2021,53(4):233-239.