镧铁共掺杂二氧化钛纳米线阵列的可见光催化性能

采用溶胶-电泳沉积技术,在多孔氧化铝模板中合成了二氧化钛(TiO2)纳米线阵列结构.研究了La3 /Fe3 共掺杂对TiO2纳米线可见光催化性能的影响,并分别与La3 ,Fe3 单掺杂TiO2纳米线可见光催化性能进行了比较.结果表明:与La3 ,Fe3 单掺杂TiO2纳米线相比,La3 /Fe3 共掺杂TiO2纳米线具有更高的可见光催化活性,光照4 h对甲基橙的降解率就达到了90%以上,大幅度提高了Ti02的可见光催化活性,这是因为2种不同体系离子的协同作用,不仅有效抑制了光生电子和空穴的复合,而且明显降低了TiO2的禁带宽度,由3.24降低到2.38.研究还表明:TiO2纳米线阵列极大的比表面积以及表面特有的性质和结构是掺杂改性TiO2纳米线具有较高可见光催化活性的重要因素.     

含银纳米晶TiO2有序多孔膜层的制备及其光学性能

以单分散聚苯乙烯(PS)微球为原料,水为稀释溶剂,利用垂直沉降法制备出多层PS球有序阵列模板.采用溶胶-凝胶法制备TiO2溶胶,并用胶晶模板法制备出锐钛矿型TiO2有序多孔薄膜.然后将金属银纳米晶掺入多孔膜骨架中制备出含银纳米晶的TiO2有序多孔发光薄膜.分析了掺银的TiO2有序多孔膜的形貌与结构,并研究了掺银的TiO2有序多孔膜吸附罗丹明B及量子点CdSe荧光物质的荧光增强性能.结果表明:掺银的TiO2薄膜基本呈现多孔结构并保留有一定的有序性.有序多孔骨架中银纳米晶的表面荧光增强作用可大幅度提升荧光物质的荧光性能,从而扩展了TiO2有序多孔薄膜在生物信息探测、光信息处理领域的应用.     

以多孔氧化铝为模板钴纳米线阵列的制备

以多孔氧化铝为模板,采用交流电沉积的方法制备了钴纳米线阵列膜.采用扫描电子显微镜(SEM)对电沉积钴纳米线前后的多孔氧化铝模板的形貌进行表征,通过透射电子显微镜(TElM)观察钴纳米线的表面形貌.结果表明:金属钴沉积到多孑L氧化铝模板的纳米孑L中,钴纳米线的平均直径约为50n/n,与氧化铝模板的孔径相一致.     

纳米TiO2颗粒在多孔铝箔上的固定及其光催化性质

本文采用溶胶-凝胶法制备了纳米TiO2颗粒并将其固定在多孔铝箔上.对固定在多孔铝箔上的纳米TiO2颗粒的光催化性能进行了研究.此外,还研究了煅烧温度以及水中无机盐对纳米TiO2颗粒光催化性能的影响.结果表明固定在多孔铝箔上的纳米TiO2颗粒具有良好的光催化性能,并且500℃下处理的纳米TiO2颗粒的光催化性能最好.水中无机盐对纳米TiO2颗粒光催化性能的影响较大,具有一定的负作用.     

氧化钛纳米线阵列的溶胶凝胶模板合成与表征

采用二次阳极氧化工艺制备了高度规则排列的多孔氧化铝（PAA）模板,并利用模板法与溶胶-凝胶法结合的模板组装技术制备了氧化钛纳米线阵列,得到了直径在50 nm左右,线间距约为50 nm的纳米线阵列.研究了模板组装过程不同压力条件对溶胶向模板孔洞中填充度的影响,发现在一定的负压条件下,有利于PAA孔中气体的排出,得到高的溶胶填充度,进而制备出高质量的纳米线阵列.分别通过SEM及XRD技术表征了PAA模板及纳米线的形貌及相结构.SEM观察发现纳米线彼此平行,表面光洁,不存在龟裂,纳米线的长度和直径与所使用模板的厚度和直径一致,表明纳米线的生长受控于模板;XRD分析表明模板为单一的θ-Al₂O₃晶型,纳米线为锐钛矿型TiO₂.     

以多孔氧化铝为模板电沉积制备磁性纳米线阵列膜

近年来,以多孔阳极氧化铝为模板制备磁性纳米线材料颇受人们的关注。综述以多孔阳极氧化铝为模板,采用电化学沉积制备各种有序磁性纳米线阵列膜的最新研究进展,同时展望磁性纳米线的应用前景。     

模板法交流电沉积铜纳米线阵列及其表征

先通过二次阳极氧化法制备多孔阳极氧化铝膜模板,再采用交流电沉积法将Cu金属填入模板的纳米孔洞中得到铜纳米线阵列。分别采用扫描电镜、透射电镜和X射线衍射仪对Cu纳米线阵列的形貌和晶体结构进行表征。结果表明,多孔氧化铝模板的孔洞排布致密、均匀而有序。交流电沉积所得Cu纳米线为单晶结构,直径为60~90 nm,长度为0.5~4.0μm。     

Co-氧化铝纳米阵列的结构与磁性研究

用二次阳极氧化法制备了多孔氧化铝膜，并以之为模板，用直流电沉积法成功地将Co金属组装入多孔氧化铝膜的纳米孔洞中，观察与测试了Co—氧化铝纳米阵列结构和磁性。结果发现，二次阳极氧化法在短时间内就能制备出较为有序的多孔氧化铝膜；Co—氧化铝纳米阵列中的Co金属纳米线有一定的结晶择优取向，并且当多孔氧化铝模板的孔径减小，择优取向发生优化；Co—氧化铝纳米阵列有明显的磁各向异性。     

填料式SO2-4/TiO2-Al2O3-Al固体酸催化合成乙酸乙酯

采用阳极氧化铝模板法(AAO)制备了Al2O3-Al一体型多孔氧化铝载体,采用电沉积技术将TiO2沉积到氧化铝多孔的纳米孔道内,制备了催化精馏用拉西环填料式TiO2-Al2O3-Al复合载体,采用浸渍法制备了SO2-4/TiO2-Al2O3-Al固体酸催化精馏元件,以乙酸乙酯的合成为模型反应考察了所制备固体酸催化剂的酯...     

钇掺杂有序多孔TiO2薄膜的制备与可见光催化性能

采用胶体晶体薄膜为模板,利用溶胶–凝胶法制备了钇掺杂有序多孔TiO2薄膜,通过Fourier变换红外光谱、扫描电子显微镜、X射线衍射、X射线光电子能谱、紫外–可见光谱表征样品的结构和形貌,并以甲基橙为模型化合物研究了钇掺杂有序多孔TiO2薄膜材料可见光催化性能。结果表明：钇掺杂有序多孔TiO2薄膜规整致密,晶型为锐钛矿型,样品中钇元素含量约为1.2%。钇掺杂使得TiO2吸收光红移至可见光区,钇掺杂有序多孔TiO2薄膜可见光催化性能好于未掺杂有序多孔TiO2薄膜。     

磷酸/草酸混合溶液中锥形多孔阳极氧化铝的制备和表征

提出了以磷酸/草酸混合溶液为电解液制备高度有序锥形多孔阳极氧化铝(PAA)模板的方法。首先采用二次氧化的方法,得到了孔洞排列高度有序且孔间距为495nm的PAA模板。在此基础上,采用阳极氧化过程和扩孔过程交替进行的方法,制备了不同长径比的有序锥形PAA模板。实验结果显示:锥形PAA模板的长径比与总氧化时间线性相关,可达到100以上;还说明了分段氧化时间和分段扩孔时间与锥形孔道形貌之间的关系。这种特殊结构的PAA模板可以大大拓展其在合成金属或半导体纳米线、光电材料以及高分子材料方面的应用范围。     

Photoluminescence of poly(thiophene) nanowires confined in porous anodic alumina membrane

Poly[3-(2-methoxyphenyl)thiophene] (PMP-Th) nanowires confined in the nano-channels of porous anodic alumina (PAA) membranes were first prepared through electrochemical deposition in cyclic voltammetry and investigated by photoluminescence (PL) spectroscopy. The morphologies and molecular structures of PMP-Th/PAA nanocomposites were studied with electron microscopy and FT-IR. The maximum absorption in UV–vis spectrum of the PMP-Th/PAA nanocomposites was located at 400–450 nm. The photoluminescence spectra show that the nanocomposites have green luminescence bands with the peaks at 560–570 nm. Compared to the electropolymerized PMP-Th film, the PMP-Th nanowires confined in the nano-channels of PAA membranes exhibit obvious blue-shifts in luminescent spectra and great enhancements in photoluminescence intensity. Further spectral analyses suggest that the PL enhancement could be attributed to Förster energy transfer from oxygen vacancies in PAA to PMP-Th molecules.     

Fine Control of Nitrogen Content in N-doped Titania Photocatalysts Prepared from Layered Titania/Isostearate Nanocomposites for High Visible-Light Photocatalytic Activity

In this contribution, high photocatalytic activity under visible-light irradiation realized by means of the fine control of the nitrogen content in doped titania photocatalysts is reported. The photocatalyst samples were prepared from a layered titania/isostearate nanocomposite as precursor, and the fine control of nitrogen content was achieved by the adjustment of the amount of hybridized isostearate in the nanocomposite, preserving the crystallinity and specific surface area of the final samples. Photocatalytic activity under the UV-light irradiation (290 and 350 nm) decreases with nitrogen content. Under visible-light irradiation (470 nm), a maximum value of photocatalytic activity was observed at [N]/[Ti] = 0.0145, whereas the absorbance in the visible-light region increases with nitrogen content. Fine control of the doped-nitrogen content provides a possible route to achieving high visible-light photocatalytic activity where the maximum value of the apparent quantum yield under 470 nm light irradiation exceeds 2%.     

Anodization of nanoimprinted titanium: a comparison with formation of porous alumina

Electrochemically prepared ordered porous alumina has become one of the most important nanotemplate materials to date. Naturally the questions arises whether other valve metals such as Ti, Ta, Nb, V, Hf or W can also be used for fabricating ordered pore arrays. We investigate in detail the electrochemical anodization of titanium in different electrolytes and its potential and temperature dependence. It turns out that due to the semiconducting properties of titania, a mirror image of the behavior of the electrically insulating porous alumina seems to be impossible. So-called porous titania in literature corresponds to the pitting regime of aluminum where pores are created due to dielectric breakdown of titania or alumina, respectively. Below the breakdown potential of titania, only thick barrier layers can be obtained. However, by nanoimprint of titanium and successive anodization below the breakdown potential, monodomain porous titanium oxide with a pore depth of 60 nm on a cm²-scale can be prepared. We discuss in detail the growth mechanism of porous structures of titanium and compare it with that of porous alumina.     

Controllable fabrication of soap-bubble-like structured polyacrylic acid nano-nets via electro-netting

Soap-bubble-like structured polyacrylic acid (PAA) nano-nets that comprise interlinked ultrathin nanowires with diameters of 10-35 nm are controllably prepared by a one-step electro-netting process.     

A study on the formation of titania nanopillars during porous anodic alumina through-mask anodization of Ti substrates

The formation of anodic titania during porous anodic alumina (PAA) through-mask anodization has been analysed for varying anodization conditions on mechanically polished bulk Ti surfaces. Titania nanopillars were formed through the porous masks in both oxalic and phosphoric acid electrolytes. For applied potentials above 40 V the titania formed along narrow channels through the alumina pore bottoms resulting in root-like attachments of the titania pillars to the Ti substrate. We further demonstrated that high-field anodization can be used for PAA through-mask anodization. The formation of titania changed with increased current density which resulted in more efficient oxide growth through the alumina pores. When the Al/Ti samples were immersed in the electrolyte without exclusively exposing the Al surface to the electrolyte the titania formed solely on top of the alumina pore bottoms which resulted in that the titania structures were detached from the Ti substrates during selective removal of the PAA templates.     

Electro-netting: fabrication of two-dimensional nano-nets for highly sensitive trimethylamine sensing

Two-dimensional (2D) polyacrylic acid (PAA) nano-nets that comprise interlinked ultrathin nanowires with diameters of 10-30 nm are successfully prepared by a facile electro-netting process. Nano-nets feature a clear geometric characteristic with ideal and weighted Steiner networks due to the rapid phase separation process and its obeyed minimal energy principle. The versatile nano-nets create enhanced interconnectivity and additional surface area and facilitate the diffusion of analytes into the membranes, which significantly boost the gas diffusion coefficient and sensing properties. As one example, PAA membranes containing fibers and nano-nets used as sensing materials are deposited by electrospinning/electro-netting on an electrode of a quartz crystal microbalance (QCM) for trimethylamine (TMA) detection, which exhibits a quick response (～180 s), low detection limit (1 ppm) and ideal selectivity at room temperature.     

Nanostructured materials prepared by use of ordered porous alumina membranes

We report on three different methods to prepare nanostructured materials using highly ordered porous alumina membranes as templates: (1) firstly, a new and simple method, termed as the paired cell method, was developed for the preparation of inorganic nanowires. Several kinds of inorganic nanowires were synthesized using this method. The structure and composition of these nanowires were determined by field emission scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy. (2) Secondly, highly ordered platinum nanowire arrays were prepared by electrochemical method with the help of porous alumina membrane templates. The structure and composition of these nanowire arrays were also characterized by various experimental techniques. The electrochemically active surface area of the nanowire arrays was determined by cyclic voltammetry based on hydrogen adsorption. Results showed that the platinum nanowire arrays exhibited a large surface area. (3) Finally, we also present a simple and reliable procedure for the preparation of highly ordered metal nanohole and nanopillar arrays, based on the anodic oxidation of aluminum and vacuum evaporation technology. The field emission scanning electron microscopic images revealed that these metal nanostructure arrays were highly ordered over a large area. The nanoimprinting of aluminum surfaces using the as-prepared chromium nanopillar arrays was demonstrated, resulting in periodic indentation on the aluminum surface.     

纳米氧化钛多孔薄膜的溶胶-凝胶法制备及其结构特征

采用溶胶-凝胶技术，以钛酸丁酯[Ti(OC4H9)4]为前驱体，加入聚乙二醇(polyethylene glycol，PEG)作为模板剂，在玻璃基片上制备了纳米氧化钛多孔薄膜。通过SEM观察了多孔薄膜的表面形貌，通过IR及XRD的测试分析表征了材料的结构，探讨了样品在溶胶-凝胶及烧结过程中的物理化学变化，测定了氧化钛的晶相成分。实验结果表明：通过调整H2O／Ti(OC4H9)4摩尔比及PEG的添加量可得到孔径范围在50～500nm且孔径可调的多孔氧化钛纳米薄膜，此外成膜过程中的升温速率是决定薄膜孔结构优劣的一个重要因素。