吸附相反应技术制备MnOxCeO2SiO2催化剂及其低温选择性催化还原NOx.pdf

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1、物理化学学报(WuliHuaxueXuebao)JulyActa尸．一Chim．Sin．2014，30(7)，1303-1308l303[Article]doi：10．3866／PKU．WHXB201405062www．whxb．pku．edu．cn吸附相反应技术制备MnO√CeO2，SiO2催化剂及其低温选择性催化还原NOx高琳心’蒋新郭森。(浙江大学化学工程与生物ST_程学系，杭州310027；浙江大学环境与资源学院，杭州310058)摘要：采用吸附相反应技术制备得到了MnOJCeOJSiO催化剂，通过X射线衍射(XRD)、透

2、射电子显微镜(TEM)、高分辨透射电子显微镜(HRTEM)、紫外激光拉曼(Raman)等手段对催化剂进行了表征．HRTEM分析表明活性组分MnO与CeO：都均匀分布在载体SiO表面：XRD分析表明Mn。O特征峰随着CeO含量的增加逐渐减小至完全消失，CeO的加入降低了MnO的结晶程度，增加了MnO的分散性：Raman光谱表明催化剂表面的Mn离子能够进入CeO晶格，激发出空穴氧，随着CeO负载量的增加，催化剂氧空穴浓度先升高后降低．以NH。为还原剂，考评催化剂的NO低温选择性催化还原(SCR)性能，催化剂催化活性随CeO负载量增加先

3、升高后降低，与催化剂氧空穴浓度变化规律一致。说明催化剂活性受氧空穴浓度影响，氧空穴浓度升高，催化剂催化活性升高．关键词：MnOJCeO／Si02催化剂：低温：选择性催化还原氧空穴：吸附相反应技术中图分类号：0643MnO】f，CeO2，SiO2CatalystsPreparedbyAdsorptionPhaseReactionTechniqueforSelectiveCatalyticReductionofNOatLow-TemperatureGAoLin．Xin’JIANGXin’，GUOSenfDepartmentofChem

4、ical＆BiologicalEngineering,ZhejiangUniversity,Hangzhou31002ZR．ChinaCollegeofEnvironmentalandResourceSciences,Zh~iangUniversity,Hangzhou310058,R．China)Abstract：MnOCeOgSiO2catalystswerepreparedbytheadsorptionphasereactiontechniqueandwerecharacterizedbyX-raydifraction(XR

5、D)，transmissionelectronmicroscopy(TEM)，high-resolutiontransmissionelectronmicroscopy(HRTEM)，andRamanspectroscopy．HRTEMshowedthatMnOandCeO2particleswereuniformlycoatedonthesur『ace0fSiO2，TheXRDspectrashowedthattheintensityoftheMn3O4difractionpeaksgraduallydecreasedandth

6、encompletelydisappearedwiththeincreasmentoftheCeO2content，whichindicatedthatCeO2reducedthecrystallinityofMnOandimprovedthedispersibilityofMnO．RamanspectroscopyindicatedthatMnionsonthesurraceofcatalystscouldenterintothelatticeofCeO2，replaceoxygenions，andf0rmoxygenvacan

7、cies．WiththeincreasmentofCeO2content．thedensityofoxygenvacanciesinitiallyincreasedandthendecreased．Weusedthecatalystsforselectivecatalyticreduction(SCR)ofNOwithNH3．ThecatalyticactivityinitiallyincreasedandthendecreasedwiththeincreasmentofCeO2content．similartothechange

8、inthedensityofoxygenvacancies．Thus，thecatalyticactivityoftheMnOJCeOJSiO2catalystsincreaseswithincreasingthedensityofoxygenva