Soft Solution Process-Based Synthesis And Properties Research Of Inorganic Functional Nanostructures

Manipulated synthesis of nanostructures is one of the hot areas in nanoscience and nanotechnology,and also the base to investigate distinctive properties and applications of nanostructures.This thesis studies soft solution-based manipulated synthesis of functional nanostructures,emphasizing on the relationship between structures and properties,and main hydrothermal carbonization reaction of simple carbohydrates,especially glucose.The main results are summarized as the following:1.Controllable synthesis of zinc-substituted nickel hydroxide nanostructures and their collective intrinsic propertiesA controllable homogeneous precipitation approach has been developed to synthesize zinc-substituted nickel hydroxide nanostructures with different Zn content from a zinc nanostructured precursor.As a typical layered double hydroxides(LDHs), zinc-substituted nickel hydroxide nanostructures can be formulated as NiZn_x(Cl)_y(OH)_2(1+x)-y·zH₂O(x=0.34-0.89,y=0-0.24,z=0-1.36).It is interesting to find that the zinc-substituted nickel hydroxide nanostructure,with the decreasing of the zinc content,has not only the morphology evolution but also the structure evolution fromα-Ni(OH)₂ phase toβ-Ni(OH)₂ phase.The complex homogeneous precipitation mechanism has been proposed for explaining the formation process of zinc-substituted nickel hydroxide nanostructures.As prepared nanostructures exhibit some exciting intrinsic properties,and their useful optical,magnetic,and electrical properties can systemic change with the decreasing zinc content.The zinc-substituted nickel hydroxide nanostructures with different Zn content display the similar optical absorbance spectra,but emission peaks shift towards shorter wavelength with decreasing Zn content of samples.Zinc-substituted nickel hydroxide nanostructures with decreasing Zn content have different magnetic properties from the magnetic behavior to the antiferromagnetic behavior.Zinc-substitutedα-nickel hydroxide nanostructures exhibit such high stability that they can stand more than 40 days in 6 M KOH.Zinc-substituted nickel hydroxide nanostructures,especiallyα-Ni(OH)₂ phase,show well electrode reversibility.2.Microwave assisted "green" synthesis of uniform silver nanoparticles and self-assembly into multilayered films with interesting optical propertyAn environmentally benign process for the synthesis of nearly monodisperse silver nanoparticles in large quantities has been developed via a microwave-assisted "green" chemistry method in aqueous system,using basic amino acids,such as L-lysine or L-arginine,as reducing agents and soluble starch as a protecting agent. The presence of such amino acids with basicity as L-lysine or L-arginine,having two amino groups in each molecule,is indispensable for the synthesis of uniform silver nanoparticles.The current synthetic process can be readily applied to large-scale production,for example,a reaction yielding 0.1 g of nearly monodisperse silver nanoparticles can be performed in a 80 mL microwave sealed vessel.Self-assembly of starch-capped silver nanoparticles result in multilayered mirror-like films forming on the glass slide surface.The surface plasmon transmission of the films has blue-shifted with decreasing the silver atom concentrations of the films.The silver films offer great surface enhancement for 4-mercaptobenzoic acid(4-MBA) molecules,and the surface enhancement factor can be efficiently changed by the silver atom concentrations of the films.3.Advances in functional carbonaceous materials from hydrothermal carbonization of biomass and main hydrothermal carbonization reactions of glucoseAn overview of the latest advances in the HTC process of functional carbonaceous materials from biomass is reviewed.These Carbonaceous materials not only have special morphology,such as nanospheres,nanocables,nanofibers, submicrocables,submicrotubes,porous structures,but also contain rich functional groups which can greatly improve hydrophilicity and chemical reactivity.A thorough investigation of the hydrothermal carbonization process of hexose,such as glucose and fructose,is conducted with the specific aim of understanding the main reactions, but more particularly for glucose including dehydration of glucose,forming linear unconjugated oligomers,conjugated and cross-linking reaction,transforming water insoluble carbonaceous materials.The formation of conjugated sequences along the poly-chains is achieved,according to repetitive cycles including the loss of hydride ions and the deprotonation of the carbenium ions,leading to the deep colour of the solution and the decreasing pH value.The branching reactions only occur after the appearance of the multiple unsaturations,forming cross-linking structures and producing water insoluble materials.The main hydrothermal carbonization reactions of glucose effectively explain some interesting phenomenon,such as the colour of the solutions becoming deeper,the decreasing of the pH value,and forming water insoluble carbonaceous materials.