Controllable Synthesis Of Metal/Metal Oxide Colloidal Nanoparticle Clusters And Their Applications

As a new type of secondary structure,colloidal nanoparticle clusters(CNCs)have attracted much attention in recent years due to their incomparable advantages over single primary nanoparticles.Various synthesis strategies,including one-step and multi-step synthesis approaches,have been developed to prepare colloidal nanoparticles.The one-step methods show many advantages,such as simple operation,high reproducibility,uniform nanocluster size,and so on.But it is quite challenging to achieve morphology control through the one-step approach.The multi-step methods are beneficial to the preparation of composite shell nanostructures.However,the operating processes are usually tedious and time-consuming.In this thesis,a series of colloidal nanoparticles clusters were successfully prepared through the one-step method or multi-step method.Additionally,these colloidal nanoparticles have been successfully applied in photonic crystals,electro-catalysis and surface enhanced Raman scattering(SERS),respectively.The main work is divided into the following three parts.1.Superparamagnetic Fe3O4 CNCs have been successfully synthesized on gram scale through a facile hydrothermal method.As-prepared Fe3O4 CNCs exhibited superior long-term charge stability without any modification.The Fe3O4 CNCs also are excellent building blocks for magnetically responsive photonic crystals,showing good photonic performance even after storing for three months.2.One simple solvothermal method is developed to prepare Pt Ni-alloyed CNCs.A series of characterizations have been carried out to investigate the growth mechanism of this special nanostructure.Besides,the as-prepared Pt Ni CNCs show great catalytic performance in methanol oxidation reaction because of their high specific surface area and steady frame structure.3.Ag CNCs has been synthesized through a localized oxidation and reduction process in the gas phase.We proposed one new synthesis strategy to prepare Ag CNCs and investigated the formation mechanism in detail based on various characterizations.In addition,the as-prepared Ag CNCs showed excellent performance in SERS.