摘要
氨选择性催化还原(NH3-SCR)技术需要进一步研发在相对较低温度(<300℃)下具有良好催化活性、高稳定性及环境友好的脱硝催化材料。本工作采用草酸共沉淀法制备Mn-Fe-O催化材料,并对其进行不同含量CeO2修饰,用于低温NH3-SCR脱硝催化反应。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、氮气吸附-脱附、X射线光电子能谱(XPS)、程序升温还原或脱附(H2-TPR、NH3-TPD)等手段对催化剂进行了表征。催化结果表明,在相同反应条件下适量CeO2修饰后的Mn-Fe-O样品比纯Mn-Fe-O表现出更优异的NH3-SCR脱硝催化性能,在80℃时NO转化率在95%以上,且具有较高的N2选择性。CeO2修饰提高了Mn-Fe-O氧化物表面的Fe^3+、Mn^3+和Mn4+含量及表面酸性位点数量,从而有助于NH3的吸附及催化反应的进行,并且Fe^2+/Fe^3+、Mn^2+/Mn^3+/Mn^4+以及Ce^3+/Ce^4+电子对之间的相互氧化还原反应提高了催化剂的氧化还原能力及稳定性。
The ammonia selective catalytic reduction(NH3-SCR) technology is still necessary to further develop denitration catalytic materials which have good catalytic activity, high stability and environmental friendliness at relatively low temperature(<300 ℃). In this work, the Mn-Fe-O catalyst was prepared by oxalate co-precipitation method and modified with different contents of CeO2 for low temperature NH3-SCR of NO. The catalysts were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), nitrogen adsorption-desorption, X-ray photoelectron spectroscopy(XPS), temperature programmed reduction or desorption(H2-TPR, NH3-TPD). The catalytic results show that as compared with pure Mn-Fe-O sample, Mn-Fe-O modified with suitable CeO2 content shows much better performance for NH3-SCR with 95% conversion of NO and a high N2 selectivity at 80℃ under the same reaction conditions. CeO2 modification increases the content of Fe^3+, Mn^3+ and Mn^4+, and the number of surface acid sites on the surface of Mn-Fe-O oxide, which contribute to the adsorption of NH3 and the catalytic reaction. In addition, redox reactions among Fe^2+/Fe^3+, Mn^2+/Mn^3+/Mn4+ and Ce^3+/Ce^4+ pairs improve the redox ability and stability of the catalyst.
作者
黄秀兵
王鹏
陶进长
席作帅
HUANG Xiubing;WANG Peng;TAO Jinzhang;XI Zuoshuai(School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China;Guangdong Provincial Key Laboratory of Rare Earth Development and Application,Guangzhou 510310,China)
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
2020年第5期573-580,共8页
Journal of Inorganic Materials
基金
国家重点研发计划项目(2018YFB0605900)
国家自然科学基金青年基金(51802015)
广东省稀土开发及应用研究重点实验室开放基金(XTKY-201803)。
