The Synthesis Of Nanoscale Materials Via Green Way And Their Performance

It is a new researching area of controlling the growth of inorganic crystals by using polysaccharide as template. Polysaccharide is the condensation polymer of saccharide, which is one of the richest renewable natural organic macromolecules on the earth. It usually has large molecular weight and has negative charges. Polyhydroxylated macromolecules present dynamic supramolecular associations facilitated by inter- and intra-molecular hydrogen bonding resulting in molecular level capsules, which can act as templates for nanoparticle growth. The structures and properties of inorganic crystals can be controlled by various kinds of polysaccharide templates with different conformation and molecular weight. It has many advantages. For example, polysaccharide is readily available, renewable and low cost. Besides, the chemical reaction for the nanomaterials using polysaccharide as the template can be carried out in aqueous system. In some reactions, polysaccharides not only can act as template agent, but also act as stabilizer and reducing agent. This method can efficiently avoid some toxic organic chemicals such as organic solvents, strong reducing agents, and fulfills the requirement of green chemistry. As compared to bulk materials, nanoscale materials catalysts exhibit perfect catalytic activities because of their large surface areas. In this paper, polysaccharide has been used as the template for the preparation of metal oxides and metals nanomaterials. And we also study the catalytic activities of resultant nanomaterials in reaction of three-component coupling of aldehyde, alkyne, and amine(A3).The main contents of this thesis are as follows:Firstly, we demonstrate an easy and environmentally friendly synthetic route to prepare NiO nanoparticles with large BET surface area by using starch as sacrificial template. The sample has favorable faradaic pseudocapacitive behavior and novel shape. The effects of the starch content and the calcination temperature on the structural parameters of the resultant NiO were studied. And the formation mechanism of the NiO nanoparticles was proposed. Furthermore, the method has also been demonstrated for the other polysaccharide and the other metal oxide (Co3O4). Secondly, carbon-protected metallic nanoparticles (nickel and cobalt) composites have been prepared by the pyrolysis of the mixture of soluble starch and acetate in N2 flow. The obtained samples possess mesoporous structures and high BET surface areas. And the obtained samples are highly stable in air and strong acid.Ag/C complex was prepared by using polysaccharide as template and reducing agent. With the three-components coupling reaction of amine, alkyne and aldehyde as prototype, the catalytic property of the nanoparticle was also studied. The propyl amine was achieved successfully with 54 % yield by using Ag/C as calatyst.Thirdly, we have prepared metal oxides hollow sphere via a hydrothermal approach. The electrochemical properties of the samples were studied. Two methods are reported. The first method: various metal salts were dissolved together with glucose in water, then metal oxides hollow spheres were prepared by heating treatment of the mixtures. The second method: 1) hydrothermal synthesis of colloidal carbon spheres, 2) the synthesis of metal oxides hollow sphere using the resulting colloidal carbon spheres as template. The resulting samples have large BET surface areas and have favorable faradaic pseudocapacitive behavior.