Controllable Synthesis Of Noble Metal Nanomaterials And The Study Of Their Properties

This dissertation is intended to develop the controllable synthesis of Au as well as its bimetallic nanomaterials. Au nanoplates, etched Au nanoplates, nanoporous Au-Pd as well as Au-Co, Au-Ni, Au-Cu bimetallic foams and the Au-Pt bimetallic dentrites. In addition, the formation mechanisms of the as-synthesized nanomaterials with different morphologies, compositions and structures have also been investigated. Meanwhile, the optical, catalytic and SERS properties of the as-synthesized products have also been studied. The details are summarized as follows:1. Controllable synthesis of gold nanoplates through a two-step temperature raising process and the study of their propertiesGold nanoplates in high yields have been successfully achieved via a two-step temperature-raising process through the reduction of hydrogen tetrachloroaurat in diethylene glycol in the presence of cetyltrimethylammonium bromide (CTAB) and poly vinyl pyrrolidone (PVP). The two-step temperature-raising process is propitious to the kinetic control of the nucleation and growth of the products. The reaction parameters on the formation of gold nanoplates were investigated.(such as, the concentrations of HAuCl4,CTAB,PVP and the reaction temperature and time.) The possible formation mechanism was investigated on the basis of the others’work. The optical and SERS properties of the product were also studied.2. Controllable synthesis of etched gold nanoplates and the study of their propertiesIn this work, dextran was selected as the reductant as well as the morphology regulation agent and dispersant through the traditional hydrothermal reaction (130℃) for the synthesis of high yield etched gold nanoplates. Effects of the concentrations HAuCl4and dextran as well as the reaction temperature and time were investigated. The formation mechanism as well as the catalytic, optical and SERS properties of the etched gold nanoplates were also well studied.3. Controllable synthesis of nanoporous Au-Pd bimetallic foams and the study of their properties Nanoporous Au-Pd bimetallic foams with a large BET surface area (20.19m2/g) were successfully achieved via a mild hydrothermal process. The influences of the reacton conditions were studied and it was found that the precursor proportions played important roles on the morphology of the final product.The formation mechanism of the nanoporous bimetallic foams has been investigated and it provides a reference for the understanding of the formation of other nanoporous bimetallic foams. The catalytic, and SERS properties of the product were also well studied.4. Controllable synthesis of Au-Pt bimetallic dendrites and the study of their propertiesAu-Pt bimetallic dentrites were successfully synthesized via a mild hydrothermal process. The influences of the precursor proportions, concentration of dextran, reaction temperature and time on the morphology of the product were investigated in the present work. The possible formation mechanism of the product was revealed. The as-synthesized product possesses high catalytic activity.