Study On Morphology Control And Electrochemical Properties Of Nanoparticles

In recent years, preparation of inorganic nanomaterials with controlled particle sizeand morphology has aroused extensive attention of researchers in the fabrication ofmodern nano-device and synthesis of functional materials. This paper aims to explore anew method to control the morphology of nanoparticle under mild conditions. Through anew low-temperature precipitation route using propylene oxide as precipitating agent, avariety of crystallized precursors such as metal chlorides （e.g., γ-Cu₂（OH）₃Cl）,hydroxideobjects （e.g., γ-FeOOH） and metal oxide nanoparticles （e.g., Mn₃O₄） wereprepared successfully via controlling the reactiong conditions（including concentration ofthe metalions, reaction environment, type of gelling agent and additives）. The preparedbasic cadmium salts were adopted as the structural template s to tailor the structure andmorphology of other basic salts. The formation mechanisms were explored, and theelectrochemical properties of α-Fe₂O₃and Co₃O₄nanoparticles were investigated. Themain works of this thesis are summarized as follows:（1） γ-Cu₂（OH）₃Cl nanoparticles with cubic shape were synthesized in the ethanolicsolution of CuCl2·H2O by using the new low-temperature precipitation route. Aftercalcination at high temperature, cubic CuO nanoparticles were prepared through the phasetransition ofγ-Cu₂（OH）₃Cl nanoparticles. The effects of reaction time, Cu²⁺concentration,type of epoxide on structure and morphology of γ-Cu₂（OH）₃Cl were discussed as well asthe reaction mechanism.（2） Mn₃O₄and Mn₂（OH）₃C1nanoparticles with cubic shape were preparedsuccessfully through the simple precipitation reaction between MnCl₂·4H₂O andpropylene oxide. Extending reaction time, increasing Mn²⁺concentration or elevatingreaction temperature will affect not only the phase of the prepared nanostructures but alsothe particle size.（3） γ-FeOOH nanobundles was synthesized from the reaction between FeCl₂·4H₂Oand propylene oxide at room temperature. Through controlling conditions such as Fe²⁺concentration, reaction temperature and additives, polymorph iron oxides were obtained. The α-Fe₂O₃nanoboundls were obtained through the high-temperature phase transitioninduced by the calcination process of γ-FeOOH nanoparticles, and the electrochemicalproperties of α-Fe₂O₃nanoparticles were studyed.（4） The CdOHCl and Cd（OH）NO₃·2H₂O nanorods prepared by the precipitationroutes were used as the structure templates in the synthesis of various hydroxy metalchloride: cubic Cu₂（OH）₃Cl and Co₂（OH）₃Cl, sheet-like Zn₅（OH）₈Cl₂（H₂O）,Sn₃O（OH）₂Cl₂hollow sphere, and PbOHCl nanospheres or nano-beam. Hexagonal CdSnano-fiber and cubic crystal CdS nanospheres were also obtained successfully using thereaction between CdOHCl/Cd（OH）NO₃·2H₂O and thioacetamide. Cubic Co₃O₄nanoparticles were generated via the calcination process of Co₂（OH）₃Cl nanoparticles, andthe electrochemical properties of Co₃O₄nanoparticles were also studyed.