预览加载中，请您耐心等待几秒...

CeO_2纳米八面体高压结构相变的Raman研究(英文).docx

预览
1/2
2/2

在线预览结束，喜欢就下载吧，查找使用更方便

下载提示 文本预览

如果您无法下载资料，请参考说明：

1、部分资料下载需要金币，请确保您的账户上有足够的金币

2、已购买过的文档，再次下载不重复扣费

3、资料包下载后请先用软件解压，在使用对应软件打开

CeO_2纳米八面体高压结构相变的Raman研究(英文) Introduction: ThestructuralandvibrationalpropertiesofCeO2havebeenstudiedextensivelyduetothediverseapplicationsofthismaterialinthefieldsofcatalysis,fuelcells,andoptoelectronics.Inrecentyears,muchattentionhasbeenpaidtothehigh-pressurephasetransitionofCeO2.Inparticular,thenanoscaleCeO2octahedrahaveshowninterestingpressure-inducedstructuralchangesthathavenotbeenobservedinbulkCeO2.Inthispaper,wepresentaRamanspectroscopicstudyofthehigh-pressurestructuralphasetransitionofCeO2nanoscaleoctahedra. Experimental: TheCeO2nanoscaleoctahedrasamplesweresynthesizedusingahydrothermalmethod.Thesampleswerethenpowderedandcompressedintoadiamondanvilcellforhigh-pressureRamanspectroscopicmeasurements.Thehigh-pressureRamanspectrawerecollectedusingamicro-Ramanspectrometerequippedwitha532-nmlaser. ResultsandDiscussion: TheRamanspectraoftheCeO2octahedrawerecollectedunderincreasingpressure.TheRamanspectrumofthelow-pressureCeO2octahedraexhibitedcharacteristicRamanpeaksat465,500,697,785,and1319cm^-1,whichcorrespondedtotheF2g,Eg,Ag,Bg,and2F2gRamanmodes,respectively.TheRamanmodeat500cm^-1correspondedtothecrystallatticevibrationoftheCeO2octahedra. Uponincreasingpressure,theRamanspectraoftheCeO2octahedrashowedsignificantchanges.Atapressureofapproximately10GPa,anewRamanpeakat215cm^-1appearedintheRamanspectrum.ThisnewRamanpeakwasattributedtotheemergenceofanewphaseofCeO2,whichischaracterizedbyahigh-pressurephasewithafluoritestructure.TheappearanceofthisRamanpeakindicatesthattheCeO2octahedrahadundergoneahigh-pressurestructuralphasetransition. Asthepressurecontinuedtoincrease,theRamanmodesoftheCeO2octahedraunderwentfurtherchanges.Atapressureofapproximately14GPa,theRamanpeakat215cm^-1disappeared,indicatingthecompletionofthehigh-pressurephasetransition.Inaddition,severalnewRamanmodesemergedintheRamanspectra,whichwereattributedtotheresponseoftheCeO2octahedratothehigh-pressureenvironment.Atapressureofapproximately20GPa,alltheRamanmodesoftheCeO2octahedrabegantoshifttohigherfrequenc