Photocatalytic Study Of New Functional Electrical Properties Of Nanomaterials And, Solvothermal Synthesis

Nanomaterials is of great interest in mechanical, magnetic, electrical, thermal,optical and catalytic fields owning to the small size effect, surface effect, themacroscopic quantum tunnel effect and quantum size effect. Great achievements havebeen made in nano-world which also promotes the wide application of nanomaterials.To date, the synthesis of function nanomaterials has relied on solid phase synthesis,liquid phase and gas phase method. Considering that much disadvantages on thesynthesis of these nanomaterial, such as complicated preparation process,energy-costing and time-wasting, we aim to explore novel and facile preparationmethod to develop new functional nanomaterials to ease environmental and energycrisis. With the help of modern scientific characterization technologies, we analyzedexperimental results and tried to put forward some new scientific concepts andthoughts. This paper mainly included the following parts.1. Ionothermal synthesis of hierarchical BiOBr microspheres for water treatmentUniform bismuth oxybromide （BiOBr） micropsheres with hierarchicalmorphologies have been fabricated via a high-yield facile ionothermal synthesis route.The composition and morphology were characterized by XRD, SEM, SAED, EXD etc.The as-prepared BiOBr nanomaterials can effectively remove heavy metal ions （Cr6+）and organic dye （MB） from wastewater. They can also kill Micrococcus lylae （a Grampositive bacterium in water） under fluorescent light irradiation. The excellentperformance may be ascribed to their hierarchical structure, allowing them highsurface to volume ratio, facile species transportation and excellent light-harvestingability.2. Microwave-assisted ionothermal synthesis of CNTs-TiO₂composites for heavymetal removalA simple and novel microwave-assisted ionothermal synthesis route was applied insynthesizing CNTs-TiO₂composites. The porous single-crystalline TiO₂crystals werewell attached on carbon nanotubes. The TiO₂particle size is about50nm. Byadjusting the reaction time, we can well control the exposure rate of {001} facets ofTiO₂. The activity of CNTs-TiO₂was evaluated by photocatalytic Cr （VI） removalunder UV light irradiation. The results demonstrated that the removal efficiency washigher than that of the commercial TiO₂. It also showed high recyclability. Theimportant role of carbon nanotubes in the photocatalytic process was also been investigated.3. Microwave synthesis of large anatase single-crystal cubes with highly reactive{010} and {001} facets and their catalytic performanceLarge anatase single-crystal cubes with {010} and {001} reactive facets wereprepared for the first time via a facile ionothermal microwave-assisted method. Thepreparation involved an aqueous solution of titanium tetrafluoride, an ionic liquid（1-methyl-imidazolium tetrafluoroborate） and sodium dodecyl benzene sulfonate（SDBS） as morphology control agents. The chemical and physical porperties of theas-prepared samples were characterized by XRD, TEM, FESEM and PL, etc. Thephotocatalytic activity of cubic anatase TiO₂was investigated by the degradation ofRhB and water spliting. These single-crystalline TiO₂crystals with cubic morphologyshowed higher photocatalytic activity for the RhB degradation and higher hydrogengeneration rate than those of {001} facet and {101} dominated anatase TiO₂.4. Synthesis of ultralong copper nanowires for high-performance transparentelectrodesUltralong single-crystalline Cu nanowires with excellent dispersibility werefabricated via a nonaqueous route. The chemical and physical properties of theas-prepared copper nanowires were characterized by XRD, TEM, FESEM. The lengthof the nanowires varied from tens to hundreds of micrometers. The average diameter ofthe nanowires was⁷8nm. These nanowires were single crystalline and grew alongthe [011] direction which were confirmed by the TEM results. The growth mechanismwas investigated by the morphology evolution via controlling the reaction time. Theas-prepared nanowires can well dispersed in toluene through ultrasound. The thin filmwas prepared by vacuum filtration method to coat copper nanowires on the glasssubstrate. Such ultralong Cu nanowire electrodes exhibited outstanding conductiveperformance of20-90Ω/sq with80-90%optical transmittance after treated at200℃in H2atmosphere.5. Microwave-induced synthesis of porous single-crystal-like TiO₂with excellentlithium storage propertiesPorous anatase TiO₂single crystals with large specific surface area and remarkablecrystalline phase-stability were fabricated via a green microwave-assisted process.Ionic liquid was chosen as both an essential structure directing agent for the formationof the {001} facets exposed TiO₂and an etching agent source for selective erosion of the exposed {001} facets, leading to robust porous framework with exposed {101}facets. The physical and chemical properties of porous anatase TiO₂single crystalarchitectures were investigated by FESEM, TEM, BET, PL, XRD. These porousanatase single crystals were thermally stable up to800℃, indicating excellentstructure stability. The product showed stable cyclability at high current rate, betterreversibility, and high Coulumbic efficiency of100%for lithium storage.