| Low-dimension Ti-based nanomaterials, such as titania or titanate nanomaterials, synthesized via hydrothermal method has always been hot area in nanoscience research, due to layered structures and large specific surface area. Numerous papers have been published focusing on morphological control, photocatalytic performance improvement and potential applications concerning low-dimension Ti-based nanomaterials. However, much more efforts need to be done to achieve a wide range of promising applications. In this paper, low-dimension Ti-based nanomaterials were intensively studied to understand the structure and photocatalytic activities of 1D Ti-based nanotubes, and the fabrication process of 2D Ti-based nanosheets as well.1D sodium titanate nanotubes were first synthesized via hydrothermal process, using P25 as raw materials. Then titanate nanotubes with various protonation degrees were obtained by controlling the concentration of hydrochloric acid applied in the post-treatment. The calculated sodium contents by ICP results were 4.996%,2.914%, 0.668%,0.192%,0.061% and 0.052% for partially protonated titanate nanotubes with nominal H+/Na+ ratio of 0,0.2,0.5,1.0,2.0 and 5.0, respectively. The sodium ions played a key role in maintaining the tubular feature of the partially protonated titanate, whose morphologies transformed from nanotubes to nanorods gradually under 450 ℃ calcination. Moreover, the effects of morphologies, composition and specific surface areas on photocatalytic degradation of methyl orange were investigated.Titania nanoparticles doped with gadolinium were synthesized via sol-gel method, using tetrabutyl titanate as raw materials, and the doping amounts were set as x%=Gd/Ti, which were 0,0.1,0.2,0.5,1.0,2.0 and 5.0, respectively. After calcination under 700 ℃, undoped titania nanoparticles were composed of rutile phase. However, the rutile phase transformed to anatase and the grain size decreased as the doping amount increased. In addition, the effects of composition and crystallinity of the gadolinium doped titania nanoparticles on the photocatalytic degradation of methyl orange were also investigated.Titania nanotubes doped with gadolinium were fabricated via a hydrothermal process in 10 M NaOH solution, using the pre-synthesized Gd-doped titania nanoparticles as raw materials. The actual doping amount of Gd-doped titania nanotubes were 0.085%, 0.131%,0.280%,0.706%,1.735% and 4.715%, which were obtained by ICP measurement for the nominal amount of 0.1%,0.2%,0.5%,1.0%,2.0% and 5.0%, respectively. Furthermore, the effects of doping amount on the composition, structure, optical properties and photocatalytic activities of the Gd-doped titania nanotubes. In addition, the influence of initial concentration of methyl orange on the photocatalytic performance of optimal nanotube photocatalyst was studied.Superparamagnetic Fe3O4 microspheres were obtained via a solvothermal method using ferric trichloride as raw materials, and the microspheres were about 198nm in diameter and assembled by tiny nanoparticles about 8nm. The Fe3O4 microspheres possessed excellent water-solubility and dispersity as forming in the confined space among the molecular chains of poly (4-styrenesulfonic acid-co-maleic acid) sodium salt (PSSMA, MA:SS=1:1), which were highly hydrophilic and negatively charged. A layer of silica was successfully coated on the surface of Fe3O4 microspheres via traditional Stober method, and this process was directly demonstrated by TEM, XRD and FTIR results. Furthermore, the influence of tetraethyl orthosilicate dosage on the coating thickness was discussed, and feeding in batches reduced the aggregation.Trilayered structure Fe3O4@SiO2 @AT was fabricated by sol-gel method based on the pre-prepared Fe3O4@SiO2 microspheres, using isopropyl titanate as raw materials. The outermost titania layer was linked with the middle silica layer by countless Ti-O-Si bonds. Then hierarchical Fe3O4@titanate structures were fabricated via a rapid hydrothermal process, and the parameters such as temperature and alkalinity were tuned in order to achieve the optimal structure. The hierarchical Fe3O4@titanate microspheres maintained the superparamagnetism and the saturation magnetization was as high as 39.6emu/g. Finally, the adsorption towards methylene blue by hierarchical Fe3O4 @titanate microspheres as recyclable adsorbents were investigated, whose adsorption amount was over 85%, and exceeding 80% after regeneration twice. Moreover, mesoporous Fe3O4@SiO2 @mSiO2 trilayered structure was constructed employing cetyltrimethyl ammonium bromide as directing agent. Besides, the comprehensive effects of experimental parameters, such as the dosage of tetraethyl orthosilicate and ammonium hydroxide, and reaction time on the morphologies and structures were investigated. |
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