The Synthesis Of Nano-structured SnO₂, Zn₂SnO₄ And The Application Of Cu₃ Mo₂O₉ In Electrochemical Biosensor

Nano-scale materials have attracted much attention because of their excellent physical and fascination chemical properties, especially semiconductor nano-materials. Controlled morphology, size, chemical composition and crystal structure in the synthesis of nano-materials process is of great significance. As an n-type wide-bandgap semiconductor, SnO2 and Zn2SnO4 is an important functional material with outstanding optical and electrical properties, which has been extensively used in gas sensors, dye-sensitized solar cells, Li-ion batteries and transparent conducting electrodes.Hydrothermal synthesis has been demonstrated to be an effective and ideal approach to achieve a variety of nanostructures. In the reaction, the chemical and physical parameters of the system, such as temperature, concentration of alkaline, reaction duration, and surfactants can be varied easily to control the kinetics and thermodynamics in the nucleation and growth of nano-crystals. Furthermore, it is well known that the phase composition, particle size and morphology play crucial roles in determining the efficiency in their properties.In this work, using SnCl2·2H2O as the tin source and NaOH as the mineralizer, the three-dimensional flower-like SnO2 were synthesized by simple glucose-assisted hydrothermal process. The self-assembled SnO2 nanostructures were aggregated with SnO2 nanorods about 200-300nm in diameter. We investigated the structure and morphology evolution of SnO2 nanostructures during the reaction under different hydrothermal conditions. The probable formation mechanism of SnO2 nanostructures in the hydrothermal reactions has been investigated.SnCl2·2H2O and Zn(NO3)2·6H2O were selected as the precursor, NaOH was acted as a mineralizer. We prepared the spinel structure via a simple hydrothermal process. The specific alkalinity in the reaction system is the main factor which affects the formation of the pure-phase ZTO. We investigate different hydrothermal conditions for instance, convertedalkalinity, temperature, duration times. The probable formation mechanism of ZTO nano-crystals in the hydrothermal reactions has been investigated.Using NaMoO4·2H2O and CUSO4 as a raw materials, we prepared copper molybdate (Cu3Mo2O9) via a simple PVP- assisted hydrothermal process. The composite film based on Nafion and copper molybdate was used as an immobilization matrix to entrap myoglobin. The composite immobilized Mb film exhibited excellent electrocatalytic response to TCA.