Solution-based Controllable Synthesis And Properties Research Of Oxides And Selenides Micro/Nanomaterials

In this paper, based on the solution methods including hydrothermal route, solvothermal approach, and solution-based deposition method, the authors achieved the controllable synthesis of various micro/nanostructures of lead chalcogenide PbE (E = S, Se, Te) and metal oxide (CuO, Cu₂O, In₂O₃).The formation mechanisms of these micro/nanostructures and their related properties have also been investigated. A hydrothermal route was used to controllably fabricate various micro/nanostructures of PbSe. The formation mechanism has been studied in detail; With the assist of poly vinyl alcohol (PVA), the authors developed a general route to synthesize PbE (E = S, Se, Te) nanocubes; A hydrothermal route has been developed, for the first time, to synthesize single-crystal CuO nanorings and nanoribbons. The formation processes of nanorings and nanoribbons were studied; By using ascorbic acid as the reductant, with the assist of surfactant, Cu₂O six-horned submicrospheres were obtained at room temperature. Their formation mechanism and transformation to octahedron-like structures were studied; The authors developed a facile route to generate porous micro/nanostructures of In₂O₃ with different phases. The gas sensing properties of the products were investigated systematically. The details are summarized as follows:1. The authors hydrothermally synthesized various shapes of PbSe including octopod-like structures, quasi-spherical nanoparticles, nanosheets, and nanocubes, by adjusting the molar ratio of NaOH/Pb(NO₃)₂ without any surfactant or in the presence of poly(vinyl pyrrolidone) (PVP). And the transformation mechanism of various shapes and formation processes of octopod-like structures and nanosheets were further studied. The above results of research have been published in Crystal Growth & Design.2. Based on the research of PbSe, from the point of different polymers on the crystal nucleation and growth, with the assist of polyvinyl alcohol (PVA), the authors developed a general route to synthesize PbS, PbSe, and PbTe nanocubes. 3. A hydrothermal route has been developed to synthesize single-crystal CuO nanoribbons and nanorings. The formation processes of nanoribbons and nanorings could be interpreted by two stages: initial nanoflakes splitting into nanoribbons due to the Brownian movement of surfactant SDBS; then these nanoribbons possessing polar surfaces coiling into nanorings to reduce the electrostatic energy. The above results of research have been published in Crystal Growth & Design.4. Based on the research of CuO, ascorbic acid as the reductant was introduced into the reacion system, Cu₂O six-horned submicrospheres were obtained at room temperature. By adjusting SDBS concentration or by adding proper amount of ethanol into the reaction solution, Cu₂O octahedra can be obtained. That the preferential adsorption of SDBS onto (111) facets of Cu₂O crystals plays an important role in the formation of six-horned submicrospheres and their transformation to octahedron-like structures.5. Hexagonal In₂O₃ microspheres, cubic In₂O₃ porous nanoparticles, and cubic In₂O₃ porous nanorectangles were fabricated by calcining precursors at 450℃, respectively. The precursors InOOH microspheres, In(OH)₃ nanoparticles, and In(OH)₃ nanorectangles were solvothermally synthesized by adjusting the volume ratios of ethylenediamine and distilled water in autoclave at 160℃.Gas-sensing properties determination of ethanol, formaldehyde, and ammonia gases show that the cubic In₂O₃ porous nanoparticles have a higher response than the hexagonal In₂O₃ microspheres. The above results of research have been published in Sensors and Actuators B: Chemical.