Colloidal Synthesis And Catalytic Applications Of Gold Nanomaterials

Noble metal nanomaterials have become the most attractive hotspots in nanotechnology because of their excellent surface plasmon resonance(SPR)properties and potential application in many fields.With the development of nanotechnology,people have made great progress in the synthesis of noble metal nanomaterials.However,the practical applications of noble metal nanomaterials have been seriously impeded by some challenges,especially the low-volume production and high cost.It is thus highly desired to develop new protocols for synthesizing nanoparticles in a large-scale and cost-effective way.In this thesis,using gold as the example,we aim to develop a simple,efficient and rapid method to synthesize gold nanoparticles,and to explore their applications in catalysis.1.We demonstrate that gold nanorods(AuNRs)can be obtained in a large-scale and cost-effective way by using an industrial gemini surfactant(P16-8-16).The surface plasmon resonance(SPR)wavelength of the gold nanorods can be tailored from the visible region to the near infrared region.Systematic studies have shown that the surfactant P16-8-16 can not only be used as a capping ligand to stabilize gold nanorods,but also can pre-reduce Au3+ to Au+ due to its carbon-carbon double bonds.In addition,we realize the synthesis of gold nanorods at a large-scale,while the cost can be significantly decreased by 90%in comparison to the conventional methods.2.The Au@Pd core-shell nanorods were prepared by a one-step synthesis method.By comparing the two synthetic systems of gold nanorods,we found that the binary surfactants system can effectively improve the morphological yield and size uniformity of Au@Pd nanorods.By varying the reaction conditions,the surface plasmon resonance properties of the Au@Pd core-shell nanorods can be tuned in a broad range.The presence of core-shell structure was confirmed by X-ray diffraction(XRD)and elemental analysis.The as-prepared Au@Pd core-shell nanorods show higher catalytic activity than palladium cube and palladium octahedral in the electrooxidation of ethanol.3.Janus nanostructured Au-SiO2 nanoparticles were successfully prepared by using polyvinylpyrrolidone(PVP)as the capping surfactant to partially modify the surface of gold nanoparticles.Through a series of exploratory experiments,we found that PVP molecules not only make the negatively charged gold nanoparticle stable in solution but also enhance the affinity between gold nanoparticles and silica.Compared with the traditional Au-SiO2 core-shell nanostructure,Au-SiO2 Janus nanostructure exhibits excellent catalytic performance in the catalytic reduction of p-nitrophenol.This work provides a rapid preparation method for eccentric Au-SiO2 and may be can extend to other similar system.