α-MnO2和β-MnO2纳米棒的制备和催化性能研究

α-MnO₂ and β-MnO₂ nanorods were prepared directly by facile hydrothermal process at 150 ℃ and 220 ℃, respectively. The as-prepared α-MnO₂ and β-MnO₂ nanorods were shown to be phase-pure single crystallites as evidenced by XRD, TEM and SEM results. Further experiments show that the as-prepared α-MnO₂ and β-MnO₂ nanorods have catalytic effect on the oxidation and decomposition of the methylene blue(MB) dye with H₂O₂. The catalytic activity of β-MnO₂ is much higher than that of α-MnO₂.     

过渡金属离子置换钛酸(盐)纳米管的合成和表征

以掺杂(Mn、Cr、Cu)的锐钛矿相二氧化钛纳米粉体为前驱体, 采用水热法合成了过渡金属离子置换的钛酸(盐)纳米管, 并用扫描电镜(SEM)、透射电镜(TEM)、能谱元素分析(EDX)、粉末X射线衍射(XRD)、 荧光发射光谱(PL)和拉曼光谱(Raman)对产物进行了表征. 结果表明, 过渡金属离子置换的钛酸(盐)纳米管荧光发射强度随金属离子的置换都有不同程度的降低, 一般认为低电子空穴对复合率意味着高光量子效率. 期望置换后的钛酸(盐)纳米管有可能在催化领域得到应用.     

BiIO_4 Nanoflakes for the Degradation of Phenol under Simulated Solar Light Irradiation

BiIO_4 nanoflakes were successfully prepared through a facile hydrothermal method. The as-prepared BiIO_4 was characterized by scanning electron microscope(SEM), high-resolution transmission electron microscopy(HRTEM), X-ray diffraction(XRD), energy-dispersive spectroscopy(EDS) and ultraviolet visible diffuse reflectance spectroscopy. BiIO_4 nanoflakes showed excellent photocatalytic activity for the degradation of phenol solution under simulated solar irradiation. The influence of synthesis temperature on the morphology, size and photocatalytic performance of BiIO_4 was investigated. BiIO_4 prepared under 140 ℃ exhibited the highest removal rate of phenol under simulated solar light irradiation. In addition, the parametric studies such as the effect of catalyst loading and phenol solution pH were carried out to optimize the reaction conditions. The active species trapping experiment demonstrated that h~+ and ·OH are the major active species during the photocatalytic process.     

纳米二氧化钛粉体表面的吸附特征及其对粉体分散性的影响

以四氯化钛(TiCl4)为原料,采用3种不同的沉淀剂制备了纳米二氧化钛粉体.用TG-DTA和FT-IR对前驱体进行了分析.结果表明,不同沉淀剂导致粉体表面状态不同.以乙酸和尿素为沉淀剂的粉体表面不仅沉淀剂可以形成化学吸附,水分子也参与反应并在粉体表面形成-OH基团,而以EDTA为沉淀剂的粉体表面只吸附沉淀剂.煅烧后,用TEM对颗粒形貌进行了表征.实验发现,以EDTA为沉淀剂制备的粉体分散性优于其他沉淀剂制备的二氧化钛颗粒.这些差异主要是由于沉淀剂的性质及其在粉体表面的吸附状态不同.     

Ag/C同轴纳米电缆的制备

采用十六烷基三甲基溴化铵(CTAB)辅助水热法合成了Ag/C同轴纳米电缆,并用SEM、TEM、XRD和EDS对产物进行了表征。结果表明,产物为长达数十微米,内核直径80～100 nm,壳厚约100 nm的纳米电缆。初步探讨了Ag/C同轴纳米电缆的生长机制。