Construction And Properties Of Rare Earth Core-Shell Magnetic-Upconverting Nanomaterials And Mesoporous Catalytic Nanomaterials

The lanthanides based luminescent nanomaterials have broad application in photoelectric device, solid state lighting, bioassay and medical diagnosis. In the choice of luminescent nanomaterials for labeling, targeting and imaging, compared with quantum dots and organic dyes, up-conversion nanoparticles (UCNPs) possess lots of advantages such as high fluorescence quantum yields, low toxicity, long lifetimes, and high stability. By combining luminescent material with magnetic material, this bi-functional material can be used as bimodal for bio-labeling and MRI imaging simultaneously. The lanthanides based catalysts also attract great interests for their excellent performance. Based on the ability of storing and releasing oxygen, CeO2is a significant component in three way catalysts, catalysts for reforming bio-ethanol or CO-PROX in PEMFC. Combining transition metal oxides (Co3O4) with ceria dioxide can further improve its ability for migrating oxygen. Promoted metal oxides supported Pt nanoparticle catalysts give rise to very promising performances in the reaction temperature range60-150℃.Based on the above background, With the help of rational design and controlled fabrication, we constructed rare earth core-shell magnetic-upconverting nanomaterial (Fe3O4@SiO2@Gd2O3:Yb,Er) and mesoporous catalytic nanomaterial (Pt/CeO2-Co3O4) with unique structures and excellent properties.The first chapter gives a brief introduction of rare earth based luminescent nanomaterials and nanocatalysts.The development of lanthnides based magnetic-upconverting nanomaterials and mesoporous catalytical nanomaterials were also discussed.In the second chapter, bi-functional Fe3O4@SiO2@Gd2O3:Yb,Er nanostructures were created and their magnetic, luminescent properties were tested. These nanoparticles are composed of magnetic Fe3O4cores, variable SiO2mid-layers, and magnetic and up-converting Gd2O3shells. The synthetic process is well-controlled and the obtained Fe3O4@SiO2@Gd2O3:Yb,Er nanoparticles show relative monodispersity and exhibit tunable magnetic and up-conversion luminescence depending on the thickness of SiO2mid-layers. These nanoparticles show distinctive red emission at662nm and could be collected by an outer magnet simultaneously. This bi-functional nanomaterial may be applicable in bioimaging.In the third chapter, we synthesized a series of highly ordered mesoporous CeO2-Co3O4supported Pt catalysts using mesoporous silica KJT-6as a hard templa^via the nanocasting method. The CeO2and Co3O4nanoparticles act as the support with highly dispersed Pt nanoparticles on them. These catalysts show outstanding catalytical activity for CO-PROX. The composition of the support, contents of loaded Pt were optimized for a better CO conversion, the3wt.%Pt/CeO2-Co3O4(7:3) showed the highest catalytic activity. The maxium conversion and selectivity could be reached to82%and44%at90℃. This catalyst may have potential value in CO-PROX reaction.The conclusion for these studies was summarised in the fourth chapter and we outlooked the subsequent works that have not been carried out.