Preparation, Characterization And Properties Of Electrochemical Methanol Oxidation By Loaded Type Tin-Based Nano Materials

Tin oxide (SnO2) is a carrier of electronic semiconductor materials, large band gap (Eg= 3.6 eV), which is generally tetragonal rutile structure, each cell contains two tin atoms and four oxygen atoms, but in the actual synthesis process which appears produce oxygen vacancies due to lack of oxygen lattice defect, showing the n-type semiconductor properties. It is because of this defect can make SnO2-based material becomes sensitive material, a conductive material and a transparent electrode material, which have important applications in gas sensors, humidity sensors, solar fuel cells and lithium-ion batteries and so on. However, in practical application process, SnO2-based materials are still have some problems such as poor circulation, circulation volume expansion and other issues, due to the existence of these problems has led to the application SnO2 based materials subject to certain restrictions..Graphene (GO) in recent years aroused great interest in the study of the carbon material of a new single-layer sheet structure, GO material unique electronic properties, excellent physical, chemical and mechanical properties, its large surface area ratio (theoretical ratio surface area of up to 2630 m2 g-1), a charge transport ability, good thermal stability and chemical stability, also in the field of sensors, adsorption, catalysis, biology and medicine, also has important applications. Research shows that the GO-based semiconductor SnO2 composite and hybrid materials, can greatly improve the performance of semiconductor optoelectronic materials SnO2 base and expand its use in lithium ion batteries, super capacitors, optical catalysts, gas and electrochemical detection.Based on the above background, this paper mean to prepare a series of material based on tin dioxide, for the electro-oxidation of methanol and in improving its catalytic activity.The first chapter reviewed the tin oxide-based materials and preparation, properties and applications of graphene-based materials.In the second chapter, introduced SiO2 as a template, using the sol-gel method and hydrothermal method, combined with the base etching method of removing the template prepared SnO2 hollow nanospheres, and by solution impregnation method, SnO2 hollow chamber internal load monodisperse noble metal nanoparticles, to build a hollow inner load SnO2 nanostructures (M@SnO2, M= Pt, Pd and Au). Through XRD, TEM, SEM characterizations of its micro-structure, size, morphology, structure, etc. were characterized and studied their catalytic performance for methanol electro-oxidation reactions.The third chapter of the hollow SnO2-based method of constructing nanostructures to SiO2 microspheres as template, using the sol-gel method and hydrothermal method, combined with the impregnating solution and multi-step method of cladding layers, and build a hollow @SnO2/GO/Pt hierarchical nanostructures. The hierarchical nanostructures with unique hollow hierarchical structure, the double-shell composed of SnO2 and GO, monodisperse Pt nanoparticles uniformly dispersed in the shell between SnO2 and GO, the three constitute a unique SnO2-Pt-GO heterojunction structure generating a strong synergism. Because of its unique hollow hierarchical structure, large specific surface area, strong synergy hollow @SnO2/GO/Pt hierarchical nanostructures exhibit good electro-catalytic properties of methanol oxidation.The forth chapter gives further hollow @SnO2/GO/Pt recycling characteristics hierarchical nanostructures, based on the work of the third chapter to nuclear Fe3O4 nanoparticles by sol-gel method, combined with the impregnating solution and multi-step method of cladding layers, by Fe3O4 nuclear outer coating SnO2 layer, and further load GO and precious metals Pt nanoparticles prepared Fe3O4@SnO2/GO/Pt hierarchical nanostructures, the nanostructures not only has the above-prepared hollow advantages @SnO2/GO/Pt hierarchical nanostructures, showing excellent performance electro-catalytic oxidation of methanol, and the expansion of the material but can also solve the problem of SnO2 catalytic process and to achieve a controllable magnetic catalyst separation.