载银TiO_2纳米线的制备及其光吸收性能

以纳米TiO2(P25)粉体为原料,采用水热法合成了TiO2纳米线,通过葡萄糖还原Ag(NH3)2+,得到了表面载银(Ag)的TiO2纳米线。利用透射电镜(TEM)、X射线光电子能谱(XPS)和紫外-可见光谱(UV-Vis)对产物进行了表征。结果表明,Ag纳米粒子均匀分散在纳米线表面,并且该Ag/TiO2纳米线在可见光区域表现出较强的吸收性能。     

介孔TiO_2和钛酸盐纳米管基的高效率染料敏化太阳能电池

介孔TiO_2和钛酸盐纳米管作为染料敏化太阳能电池的电极材料,在AM 1.5 (100mW/cm)的条件下,得到的最高光电转换效率分别为10.0%和7.5%。这样的高效率可以归因于它们的物理化学特性,包括高比表面积,规则的结构,颗粒尺寸和相互交错的网络结构。     

TiO_2/ZnO纳米管的制备及其光催化性能

采用电化学阳极氧化法制备了高度有序的TiO2纳米管阵列,并利用纳米管的光致超亲水特性,采用斜面毛细组装技术在无定形TiO2表面自组装ZnO溶胶后退火制备了TiO2/ZnO复合纳米管.探讨了阳极氧化各参数对纳米管形貌的影响.利用X射线衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)等方法对样品的结构和形貌进行了表征.以有机磷农药氯胺磷为光催化降解对象,研究了焙烧温度、管径、管长和TiO2/ZnO复合比例等因素对降解效果的影响.结果表明,焙烧温度、管径以及ZnO复合比例对光催化降解率影响较大.对于管径97 nm、管长315.8nm的TiO2/ZnO纳米管,ZnO最佳复合比例为4.2%(质量分数),5 h后降解率达到78%.     

胶溶法合成 TiO_2超微粒子

用胶溶法合成了 TiO_2超微粒子。研究了反应物浓度、胶溶剂用量、胶溶温度对胶溶过程的影响,以及表面活性剂 DBS 的量与 Ti 萃取率的关系。探讨了合成超微粒子 TiO_2的最佳条件,分析了产品的特性。200℃热处理得到的产品为非晶型圆球状,粒度均匀,平均6.0nm,在许多有机溶剂中具有良好的分散性和透明性。550℃得到晶态锐钛矿型超微粒子 TiO_2,粒度为8.5nm。700℃热处理得到金红石型TiO_2,粒度为33.2nm。     

TiO_2纳米薄膜光催化剂制备技术的新进展

综述了TiO_2纳米薄膜光催化剂制备方法的最新进展,讨论了传统技术的新发展如改进的溶胶-凝胶法和微波辅助沉积法,同时也详述了水热溶剂热法、原位生长法及自组装法等新型制备技术,最后提出了TiO_2纳米薄膜制备技术今后的发展方向.     

光催化TiO_2复合分离膜的制备技术

纳米TiO2复合分离膜集过滤、光催化降解、自清洁、防垢、提高膜通量等功能于一体,能有效解决传统膜分离系统存在的膜污染和膜通量衰减的问题,对发展新型的膜分离技术、开发纳米光催化新材料,以及在节水减排和中水回用等方面具有重要的应用价值。TiO2复合分离膜涉及TiO2纳米晶的合成和固载化工艺、多孔陶瓷载体的选择、烧结工艺及复合膜的稳定性。本文对目前国内外使用的TiO2复合分离膜的各种制备工艺和方法进行了归纳、总结和分析,并对其今后的发展和应用提供了建议。     

TiO_2纳米管/碳纳米管复合材料光催化降解玫瑰红染料废水的研究

主要介绍水热法制备TiO2纳米管/碳纳米管(TiO2/CNT)复合材料及其光催化降解染料废水的研究。结果表明,用水热法制备出的TiO2纳米管和CNT的掺杂比例为5∶1时,TiO2纳米管/碳纳米管(TiO2/CNT)复合材料光催化降解玫瑰红染料废水的效果最佳,而且TiO2纳米管/碳纳米管复合材料具有较好的稳定性。研究证实了TiO2纳米管/碳纳米管复合材料对玫瑰红染料废水在模拟太阳光照射下具有较好的光催化效果。     

TiO_2纳米管载microRNA涂层的制备及性能研究

利用阳极氧化法在纯Ti表面制得TiO2纳米管,随后用冻干法在纳米管中负载microRNA制得复合涂层。利用SEM、TEM和荧光显微镜对TiO2/microRNA复合涂层进行表征,并对microRNA的释放行为以及其进入成骨细胞后的功效进行分析。结果表明,microRNA分子成功负载在TiO2纳米管中,并在12h内持续稳定释放投递,荧光照片表明投递的microRNA成功进入成骨细胞,ALP活性测定进一步表明进入细胞中microRNA促进了成骨分化。     

软模板法制备SiO2纳米管

本文报道了以酒石酸为模板剂,正硅酸乙酯（TEOS）为硅源,乙醇为共溶剂,在氨水存在的条件下合成SiO2纳米管的方法和结果。讨论了氨水浓度对SiO2纳米管的形态和生长的影响。实验发现,氨水浓度对SiO2纳米管的形态及生长起着至关重要的作用。在一定的浓度范围内,随着氨水浓度的减小,产物中SiO2纳米管的数量和长径比都增加。并首次讨论了氨水浓度和酒石酸对SiO2纳米管形成过程的作用机理。     

TiO_2的光催化性能研究

利用第一性原理计算方法主要对非金属掺杂TiO_2可见光光催化活性进行了研究,揭示了非金属掺杂TiO_2在可见光条件下催化活性提高的本质规律。就目前为止,非金属掺杂TiO_2吸收可见光的原因主要归结为以下几点:(1)非金属掺杂引起能带变窄,从而降低光子跃迁能隙,产生可见光红移现象;(2)掺杂元素在TiO_2带隙中引入一部分间隙态,充当光子跃迁的过渡能级,减少光子吸收能量;(3)掺杂促使TiO_2产生结晶化,加大TiO_2颗粒的表面积,从而提高其催化活性。     

Fabrication and characterization of novel Ag2O-polyimide composites with enhanced visible-light photocatalytic activity

Novel high-efficiency visible-light photocatalyst, silver oxide (Ag₂O)-polyimide (PI) photocatalyst is synthesized by a liquid phase reaction method. The obtained samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectra (FT-IR) and photoluminescence (PL). The photocatalytic activity of the Ag₂O-PI composites are evaluated by the decomposition of Rhodamine B (RhB) under visible-light irradiation. All Ag₂O-PI composite possesses higher photocatalytic activity than pure Ag₂O and PI. It could be found that RhB was photodegraded with the highest degradation efficiency of 97.9% when the mass ratio of Ag₂O and PI reached to 2:1. This enhancement can be attributed to the efficient separation of photogenerated electron and holes. Furthermore, the possible mechanism for the photocatalytic activity of Ag₂O-PI composites was also proposed.     

Histidine functionalised biocompatible CdS quantum dots synthesised by sonochemical method

Histidine functionalised CdS quantum dots (QDs) have been synthesised by sonochemical method. Transmission Electron Microscopy (TEM) observation shows that the histidine functionalised CdS QDs are well-defined, nearly spherical particles. The X-ray diffraction pattern indicates formation of cubic phase of CdS/histidine QDs. The absorption spectra confirm quantum confinement of histidine functionalised CdS QDs. The photoluminescence property of CdS/histidine QDs is found better than that of CdS QDs. Histidine functionalised CdS QDs, in which histidine acts as a biocompatibiliser, can find potential applications in the biological fields.     

阳极氧化TiO_2纳米线生长研究

采用NH4F-乙二醇-H2O溶液体系的电化学阳极氧化法,在金属钛基板上形成厚度为0.9~36μm的TiO2纳米管阵列。研究了阳极氧化电压、氧化时间及电解液的组成对TiO2纳米管阵列结构的影响。结果表明,当醇水体积比为39∶1时,60V电压下氧化2h,TiO2纳米管顶部的氧化层在缺陷处发生二次击穿溶解,产生自组装的孔核,场助溶解驱动力使纳米管顶部在孔核处沿管轴向垂直劈裂,形成直径20nm、长度可达几微米的TiO2纳米线。     

Noncovalent attachment of CdSe quantum dots to single wall carbon nanotubes

Noncovalent attachment of CdSe quantum dots (QDs) to single wall carbon nanotubes (SWNTs) through an intermediary 1-pyrenebutyric acid N-hydroxy-succinimide ester (PBASE) molecule has been performed. The ligand exchange process from trioctylphosphine oxide (TOPO)-capped CdSe to the 4-aminothiophenol (ATP) ligand is supported by solvent solubility, NMR spectroscopy, and IR spectroscopy, with an estimated molecular efficiency > 50:1. Noncovalent coupling of the PBASE molecule causes a redshift in the SWNT interband electronic transitions, consistent with a π–π interaction that promotes electron delocalization. TEM analysis after chemical coupling of the CdSe–ATP QDs to the PBASE–SWNTs shows an abundant coverage of QDs along the SWNT bundles. Raman spectra (1.96 eV excitation) of PBASE–SWNTs and the noncovalent product demonstrate that each of the major Raman modes (RBM, D-, G-, or G′-bands) is unaltered by the noncovalent interaction with PBASE or attachment of CdSe QDs, indicating that the structural integrity of the SWNTs is maintained. However, upshifts in the Raman modes are observed, the largest being for the G′-band, indicating charge transfer between the SWNTs and attached CdSe QDs.     

钛酸盐中钠离子含量对其水热转化制备TiO_2纳米材料的影响

采用水热法制备了单晶TiO2纳米材料。用X射线衍射仪和透射电子显微镜对产物的晶相组成和形貌进行了表征。考查了钛酸盐中钠离子含量对其水热转化所得TiO2产物的相组成、形貌和尺寸的影响。当pH值为1,含有钠离子时,得到的是以菱形为主的直径为10nm左右的单晶锐钛矿纳米颗粒,不含钠离子时,得到的产物以单晶锐钛矿纳米颗粒为主,同时含有少量单晶金红石纳米棒。当pH值为4,含有钠离子时,得到的是具有高长径比的单晶锐钛矿纳米棒,宽为60nm左右,长为300～500nm左右,不含钠离子时,得到的是尺寸为20nm×60nm的短纳米棒。同时,探讨了钛酸盐中钠离子的影响机理。     

量子点2D-3D完整生长过程的Monte Carlo模拟

利用蒙特卡罗模拟方法对GaAs衬底上MBE法自组织生长InAs量子点的过程进行了研究,完成了量子点二维到三维生长完整过程的模拟.充分考虑应力应变的影响因素,首次使用指数函数形式的应力应变模型,使模拟结果更加可靠.通过改变衬底温度, 生长停顿时间,得到了不同条件下量子点生长的计算机模拟图形并对结果进行了讨论.结果发现,适中的温度和较充分的迁移时间有助于生长出高质量的量子点.     

Synthesis and characterization of CdTe quantum dots embedded gelatin nanoparticles via a two-step desolvation method

Novel CdTe quantum dots (QDs) embedded gelatin nanoparticles (CdTe/gelatin nanoparticles) were synthesized via a two-step desolvation method. The morphology and size distribution of the nanoparticles were characterized by transmission electron microscope (TEM) and laser particle size analyzer. They are presented spherically and relatively uniform with a diameter of 150 nm. The luminescent properties of the nanoparticles were investigated by using fluorescence spectrophotometry and fluorescence microscopy. The fluorescence stability of nanoparticles was tested in vitro. It was found that the nanoparticles were stable in water and phosphate-buffered saline (PBS) solution (pH 7.4) for at least 15 days. A possible formation mechanism of the CdTe/gelatin nanoparticles was also proposed. The inherent stability and biocompatibility indicate that the nanoparticles are expected to be promising candidates for in vivo biological imaging studies.     

Synthesis and characterisation of MoS2 quantum dots by liquid nitrogen quenching

Among transition metal dichalcogenides family, molybdenum disulphide (MoS₂) nanomaterial has a vital role in two-dimensional field due to its intrinsic optical and electronic properties. In this study, we report a new top-down approach for synthesising MoS₂ quantum dots (QDs). This strategy consists of liquid nitrogen (LN2) quenching of bulk MoS₂ material followed by two processes, probe sonication and ultra-centrifugation. This approach is simple, cost effective and eco-friendly. The structural, optical and morphological properties of obtained MoS₂ quantum dots were characterised. Photoluminescence spectra (PL) of the synthesised MoS₂ QDs show blue light emission when excited with ultraviolet radiation (365?nm). A significant observation in this study is that, the peak position of photoluminescence (PL) emission spectra is independent of excitation wavelength. In addition, a higher fluorescence quantum yield was obtained for the present MoS₂ QDs compared to MoS₂ QDs prepared by other methods.     

二氧化钛纳米管生物膜的通透性能研究

介绍了两端通透的二氧化钛纳米管阵列的制备过程,并对形貌进行了分析,给出了刻蚀纳米管阵列底部的参数;在此基础上,采用自制的通透装置,运用光电比色计和紫外分光光度计对比分析了苯酚红和牛血清白蛋白的通透性能,考察了通透时间和纳米管管径等参数对通透性能的影响规律。     

硅掺杂TiO2纳米管阵列的制备及光电催化活性的研究

通过电化学沉积,在阳极氧化法制备的高度有序TiO2纳米管阵列表面均匀地沉积Si元素.扫描电子显微照片显示Si掺杂的TiO2纳米管垂直于基底定向生长.X射线衍射分析表明,所引入的Si可能掺入到TiO2的晶格中,因而提高了TiO2的热稳定性,抑制了金红石相的生成及晶粒的长大.紫外-可见漫反射分析表明Si掺杂的TiO2纳米管吸收边带发生了明显的蓝移,并且在紫外区的吸收强度明显增强.与未掺杂的TiO2纳米管相比,Si掺杂TiO2纳米管电极的紫外光电化学响应显著提高,其光电流密度是未掺杂的1.48倍.硅掺杂TiO2纳米管阵列光电催化降解五氯酚的动力学常数(1.651h-1)是未掺杂TiO2纳米管电极(0.823h-1)的2.0倍.