MicrostructuralstudyofdifferentLDHmorphologiesobtained via differentsynthesisroutes

摘要

In ordertobetterunderstandtherelationshipbetweenLDHsynthesisparametersandtheirparticle sizes,diversecarbonateintercalatedNiAl–LDHphaseswerepreparedusingdifferentcoprecipitation conditionsandtheirstructure,microstructureandmorphologywerecharacterized.Thesampleswere synthesizedbycoprecipitationeitheratconstantpH,instrongalkalinemediumorusingurea decomposition.Theinfluenceofapost-synthesishydrothermaltreatmentwasalsoinvestigated.Awell crystallineNiAl–CO3 phase butcontainingahighstackingfaultdensitywasobtainedbycombininga strong basicmediumandhydrothermaltreatmentat120 1C for24h.Interestingly,thehydrothermal treatmentincreasesthecrystallinityofthesamplesbutdoesnoteliminatestackingfaults.The crystallitesizesdeterminedbymodelingX-raydiffractionpeakbroadeningwithlinearcombinationsof sphericalharmonicsarefullyconsistentwithTEMobservationsconfirmingthevalidityoftheapproach usedandindicatingthattheparticlesareprobablysmallsinglecrystals.