共查询到20条相似文献,搜索用时 31 毫秒
1.
G. S. Zakharova 《Russian Journal of Inorganic Chemistry》2014,59(2):24-28
Anatase titanium dioxide nanotubes were prepared by hydrothermal synthesis with subsequent annealing in a nitrogen atmosphere. The outer diameter of particles is 10–15 nm, their inner diameter is 4–6 nm, and their length is several hundreds of nanometers. The structural transformation of polytitanic acid to TiO2, which preserves the tubular morphology until 500°C, was studied by X-ray powder diffraction and thermal analyses, scanning and transmission electron microscopies, and IR and Raman spectroscopies. 相似文献
2.
Porous tetragonal BaTiO 3 ceramic was successfully prepared by a combination of hydrothermal and low-temperature-sintering method.The hollow TiO2@BaCO 3 as the sintering precursor was synthesized via a simple hydrothermal method,and then porous BaTiO 3 was generated by calcining the hollow TiO2@BaCO 3 precursor at 900 ℃ without additive.The hollow TiO2@BaCO 3 structure plays two important roles in the preparing of the porous BaTiO 3 ceramic.First,the TiO2@BaCO 3 hollow structure provides high surface areas and increases the contact points between BaCO 3 and TiO2,which can reduce the sintering temperature of the BaTiO 3 ceramic.Second,the cavity of the ordered arranged TiO2@BaCO 3 hollow sphere shows important influence on the porous structure,and the pore size of the as-prepared porous BaTiO 3 ceramic can be tuned from several nanometers to hundreds nanomters by changing the sintering temperature.The formation mechanism of the porous BaTiO 3 ceramic was proposed. 相似文献
3.
The shell-in-shell structured TiO2 hollow microspheres with enhanced light scattering ability were synthesized via a facile one step hydrothermal process. The diameter of the microsphere is about 1.5 μm, the core of the unique shell-in-shell structure is composed of TiO2 nanoparticles with a diameter of about 15 nm, while the shell is constructed with ∼50 nm TiO2 nanocubes. The hollow space between the outer shell and the inner shell is about 230 nm. The formation mechanism of the unique shell-in-shell structure is interpreted. The design and the optimized application of shell-in-shell structured TiO2 hollow microspheres in the light-trapping perovskite solar cells are also investigated. Owing to the light scattering properties of the shell-in-shell structure of the hollow microsphere, the optimized photoelectrode exhibits an enhanced photoelectric conversion efficiency of 4.29% using perovskite CH3NH3PbI3 as the sensitizer. The shell-in-shell hollow TiO2 microsphere shows a 21.2% increase in conversion efficiency when compared with P25 nanoparticels photoanode. The conversion efficiency enhancement is mainly attributed to the increase of short-current density induced by the light scattering effect. 相似文献
4.
Crystalline TiO2 nanowire-nanoparticle hetero-structures were successfully synthesized from titanium foils by using a simple thermal annealing method with the aid of CuCl2 at the atmospheric pressure. Nanowires were grown from Ti foils by simply annealing Ti foils at 850 °C. Then, TiCl4 was delivered to TiO2 nanowires so as to precipitate TiO2 nanoparticles on nanowire surfaces. At 750 °C reaction temperature, nanoparticles of tens of nanometers in diameter were well distributed on pre-grown nanowire forests. Nanoparticles were likely to be precipitated by TiCl4 decomposition or oxidation and that require high temperatures above ∼650 °C. Electron microscopy, X-ray diffraction, and UV-vis spectroscopy analyses show they have the rutile polycrystalline structure with a slightly enlarged bandgap compared to that of bulk TiO2. The influence of key synthesis parameters including reaction temperature, reaction time, and quantity of supplied materials on the incorporating nanoparticles was also systematically studied. The optimum reaction condition in the present paper was identified to be 750 °C annealing with repetitive 20 min reactions. A higher reaction temperature yielded larger diameter particles, and higher loading of Ti produced dense particles without changing the particle size. Finally, this method could be utilized for synthesizing other metal oxide nanowires-nanoparticle hetero-structures. 相似文献
5.
Naser Mohammadi Juan Carlos Abrego-Martinez Mohamed Mohamedi 《Molecules (Basel, Switzerland)》2022,27(6)
We report here the synthesis of binderless and template-less three-dimensional (3D) pinecone-shaped Pt/TiO2/Ti mesh structure. The TiO2 hydrothermally synthesized onto Ti mesh is composed of a mixture of flower-like nanorods and vertically aligned bar-shaped structures, whereas Pt film grown by pulsed laser deposition displays a smooth surface. XRD analyses reveal an average crystallite size of 41.4 nm and 68.5 nm of the TiO2 nanorods and Pt, respectively. In H2SO4 solution, the platinum oxide formation at the Pt/TiO2/Ti mesh electrode is 180 mV more negative than that at the Pt/Ti mesh electrode, indicating that TiO2 provides oxygeneous species at lower potentials, which will facilitate the removal of CO-like intermediates and accelerate an ethanol oxidation reaction (EOR). Indeed, the Pt/TiO2/Ti mesh catalyst exhibits current activity of 1.19 mA towards an EOR at a remarkably superior rate of 4.4 times that of the Pt/Ti mesh electrode (0.27 mA). Moreover, the presence of TiO2 as a support to Pt delivers a steady-state current of 2.1 mA, with an increment in durability of 6.6 times compared to Pt/Ti mesh (0.32 mA). Pt is chosen here as a benchmark catalyst and we believe that with catalysts that perform better than Pt, such 3D pinecone structures can be useful for a variety of catalytic or photoelectrochemical reactions. 相似文献
6.
Heyi Liu Xiangjun Zhou Yan Chen Tao Li Shiguang Pei 《Journal of Sol-Gel Science and Technology》2014,71(1):102-108
A new study of the preparation of nanocrystalline titanium dioxide (TiO2) fibers is reported in the paper, which were prepared by sol–gel process with titanium acetate [Ti(CH3COO)4] as precursor. After that, centrifugal spinning and steam atmosphere heat-treatment were used to obtain final fibers. Here, the molecule structure of precursor was analyzed and the TiO2 fibers obtained were characterized. Additionally, the effects of the silica (SiO2) doping were discussed in this paper. By the Fourier transformation infrared spectrum analysis, the chain structure of –O–Ti–O–Ti–O– was confirmed in the Ti(CH3COO)4 precursor, as a result the precursor spinning solution showed a good spinning performance. And the pyrolysis process of precursor fibers was analyzed with the help of DSC–TG method. The phase of TiO2 fibers obtained after heat-treatment with steam atmosphere was characterized mainly by the X-ray diffractometer (XRD), from the XRD curves, the result that the SiO2 doping can efficiently inhibit the grain growth of TiO2 fibers could also be verified. The microstructure of the TiO2 fibers was observed by scanning electron microscope, which showed that diameter of TiO2 fibers obtained with excellent continuity are from 5 to 10 μm. At last, the photocatalytic property of TiO2 fibers was also tested. 相似文献
7.
Jia Tang Peng Yin Xiaohui Lu Dawei Qi Yu Mao Chunhui Deng Pengyuan Yang Xiangmin Zhang 《Journal of chromatography. A》2010,1217(15):2197-2205
In this study, mesoporous TiO2 microspheres were synthesized by simple hydrothermal reaction, and successfully developed for phosphopeptides enrichment from both standard protein digestion and real biological sample such as rat brain tissue extract. The mesoporous TiO2 microspheres (the diameter size of about 1.0 μm) obtained by simple hydrothermal method were found to have a specific surface area of 84.98 m2/g, which is much larger than smooth TiO2 microspheres with same size. The surface area of mesoporous TiO2 microspheres is almost two times of commercial TiO2 nanoparticle (a diameter of 90 nm). Using standard proteins digestion and real biological samples, the superior selectivity and capacity of mesoporous TiO2 microspheres for the enrichment of phosphorylated peptides than that of commercial TiO2 nanoparticles and TiO2 microspheres was also observed. It has been demonstrated that mesoporous TiO2 microspheres have powerful potential for selective enrichment of phosphorylated peptides. Moreover, the preparation of the mesoporous TiO2 microspheres obtained by the hydrothermal reaction is easy, simple and low-cost. These mesoporous TiO2 microspheres with the ability of large scale synthesis can widely be applied for phosphorylated proteomic research. 相似文献
8.
In this study, inverse opal TiO2‐x photonic crystals (IO‐TiO2‐x) have been successfully synthesized by a two‐step calcination. The whole synthesis is safe and feasible. Additionly, the reduction degree and the structure of IO‐TiO2‐x can be precisely controlled. A series of IO‐TiO2‐x samples with different reduction degree were prepared and characterized. The TEM images show that the obtained samples possess a 3D‐ordered macroporous inverse opal structure. The reduced Ti atoms/oxygen vacancies were confirmed by Raman and XPS spectroscopy. All IO‐TiO2‐x samples showed better photoelectric properties than those of common TiO2 which indicates their great potential to be applied to photoelectric fields. The improvement of photoelectric properties is attributed to the efficient electron‐hole separation efficiency induced by moderately reduced Ti atoms/oxygen vacancies. Meanwhile, the 3D‐ordered macroporous inverse opal structure and the band gap are regulated to “capture” more solar energy. This new approach is proven to be a meaningful method to synthesize high‐performance TiO2 materials. 相似文献
9.
Urchin-like Co3O4 Nanostructure and Their Electrochemical Behavior in Rechargeable Lithium Ion Battery
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3D urchin-like Co3O4 have been successfully prepared by calcination of the urchin-like pre-cursors, which were synthesized through a facile hydrothermal route. The morphology and structure of the 3D urchin-like Co3O4 have been characterized by field emission scanning electron microscopy, transmission electron microscopy, high resolution transmission elec-tron microscopy, and X-ray powder diffraction. The as-synthesized Co3O4 products are of urchin-like structures with approximated 5-7 μm in diameter, and are composed of numer-ous nanoparticles chains with the particles diameter of about 15 nm. This kind of urchin-like Co3O4 exhibits superior energy storage properties with the high capacity of 1.369 Ah/g and its good cyclic stability shows great potential in the rechargeable Li-ion battery. 相似文献
10.
A.L. Castro M.D. Carvalho L.P. Ferreira J.-C. Jumas M.H. Florêncio 《Journal of solid state chemistry》2009,182(7):1838-1845
Doped titanium dioxide nanopowders (M:TiO2; M=Fe, Co, Nb, Sb) with anatase structure were successfully synthesized through an hydrothermal route preceded by a precipitation doping step. Structural and morphological characterizations were performed by powder XRD and TEM. Thermodynamic stability studies allowed to conclude that the anatase structure is highly stable for all doped TiO2 prepared compounds. The photocatalytic efficiency of the synthesized nanopowders was tested and the results showed an appreciable enhancement in the photoactivity of the Sb:TiO2 and Nb:TiO2, whereas no photocatalytic activity was detected for the Fe:TiO2 and Co:TiO2 nanopowders. These results were correlated to the doping ions oxidation states, determined by Mössbauer spectroscopy and magnetization data. 相似文献
11.
Mirghasem Hosseini Mohamad Mohsen Momeni 《Journal of Solid State Electrochemistry》2010,14(6):1109-1115
Au/TiO2/Ti electrode was prepared by a two-step process of anodic oxidation of titanium followed by cathodic electrodeposition of
gold on resulted TiO2. The morphology and surface analysis of Au/TiO2/Ti electrodes was investigated using scanning electron microscopy and EDAX, respectively. The results indicated that gold
particles were homogeneously deposited on the surface of TiO2 nanotubes. The nanotubular TiO2 layers consist of individual tubes of about 60–90 nm in diameter, and the electrode surface was covered by gold particles
with a diameter of about 100–200 nm which are distributed evenly on the titanium dioxide nanotubes. This nanotubular TiO2 support provides a high surface area and therefore enhances the electrocatalytic activity of Au/TiO2/Ti electrode. The electrocatalytic behavior of Au/TiO2/Ti electrodes in the glucose electro-oxidation was studied by cyclic voltammetry. The results showed that Au/TiO2/Ti electrodes exhibit a considerably higher electrocatalytic activity toward the glucose oxidation than that of gold electrode. 相似文献
12.
花状TiO2分级结构的可控合成与其光催化性能 总被引:1,自引:0,他引:1
采用水热法可控合成了花状TiO2分级结构材料,运用扫描电镜、透射电镜、X射线衍射、N2物理吸附-脱附等手段,对其进行了表征,系统研究了NaOH用量、H2O2浓度、HNO3浓度、反应温度及时间等因素对所得样品形貌的影响,并评价了它们的光催化性能.结果表明,花状TiO2分级结构为锐钛矿相,颗粒大小均一;随制备条件的变化,构成花状TiO2分级结构的基元结构分别为纳米线、纳米片,纳米线直径约25nm,纳米片厚度不足10nm;该样品具有较高的比表面积,表现出良好的单次光催化活性与重复使用性能. 相似文献
13.
Li Fang Enyi Hu Xiaojian Hu Zheng Jiang M. A. K. Yousaf Shah Jun Wang Dr. Faze Wang 《Chemphyschem》2022,23(11):e202200170
Lately, semiconductor-membrane fuel cells (SMFCs) have attained significant interest and great attention due to the deliverance of high performance at low operational temperatures, <550 °C. This work has synthesized the nanocomposite core-shell heterostructure (TiO2−SrTiO3) electrolyte powder by employing the simple hydrothermal method for the SMFC. The SrTiO3 was grown in situ on the surface of TiO2 to form a core-shell structure. A heterojunction mechanism based on the energy band structure is proposed to explain the ion transport pathway and promoted protonic conductivity. The core-shell heterostructure (TiO2−SrTiO3) was utilized as an electrolyte to reach the peak power density of 951 mW cm−2 with an open-circuit voltage of 1.075 V at 550 °C. The formation of core-shell heterostructure among TiO2 and SrTiO3 causes redistribution of charges and establishes a depletion region at the interface, which confined the protons′ transport on the surface layer with accelerated ion transport and lower activation energy. The current work reveals novel insights to understand enhanced proton transport and unique methodology to develop low-temperature ceramic fuel cells with high performance. 相似文献
14.
TiO2 Nanospheres: A Facile Size‐Tunable Synthesis and Effective Light‐Harvesting Layer for Dye‐Sensitized Solar Cells
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Dr. Shuan Wang Yong Ding Dr. Sichao Xu Prof. Yunxia Zhang Prof. Guanghai Li Prof. Linhua Hu Prof. Songyuan Dai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(17):4916-4920
A facile route to synthesize amorphous TiO2 nanospheres by a controlled oxidation and hydrolysis process without any structure‐directing agents or templates is presented. The size of the amorphous TiO2 nanospheres can be easily turned from 20 to 1500 nm by adjusting either the Ti species or ethanol content in the reaction solution. The phase structure of nanospheres can be controlled by hydrothermal treatment. The TiO2 nanospheres show excellent size‐dependent light‐scattering effects and can be structured into a light‐harvesting layer for dye‐sensitized solar cells with a quite high power conversion efficiency of 9.25 %. 相似文献
15.
水热法制备TiO_2纳米线薄膜的光生阴极保护性能 总被引:2,自引:0,他引:2
应用水热法在钛箔表面制备TiO2纳米线薄膜,采用场发射扫描电子显微镜、X射线衍射和紫外-可见分光光度法对薄膜进行表征,用电极电位和电化学阻抗谱考察TiO2光生阴极保护性能.结果表明:薄膜由纵横交错的锐钛矿型TiO2纳米线组成,纳米线的直径约10nm.在150℃下反应6h生成的TiO2纳米线薄膜在0.3mol·L-1 Na2SO4溶液和0.3mol·L-1 Na2SO4+0.5mol·L-1 HCOOH混合溶液中对与TiO2薄膜耦连的403不锈钢均有良好的阴极保护效应.TiO2膜所在溶液中含有HCOOH时,可使耦连的403不锈钢在0.5mol·L-1 NaCl溶液中电极电位负移约545mV,界面反应电阻显著变小,表明电解质溶液加入HCOOH可以增强TiO2纳米线薄膜对403不锈钢的光生阴极保护效应. 相似文献
16.
Junseo Choi Ji-Young Ban Suk-Jin Choung Jinsoo Kim Haznan Abimanyu Kye Sang Yoo 《Journal of Sol-Gel Science and Technology》2007,44(1):21-28
Mesoporous TiO2/γ-Al2O3 composite granules were prepared by combining sol–gel/oil-drop method, using various titania solution. The product granules
can be used as a photocatalyst or adsorbent in moving, fluidized bed reactors. The phase composition and pore structure of
the granules can be controlled by calcination temperature and using different titania solution. In the photocatalysis of NH3 decomposition, TiO2/γ-Al2O3 granules using Degussa P25 powder treated thermally at 450 °C showed the highest catalytic ability. However, TiO2/γ-Al2O3 granules using titania made by hydrothermal method had comparable performance in NH3 decomposition. 相似文献
17.
In Situ Preparation of a Ti3+ Self‐Doped TiO2 Film with Enhanced Activity as Photoanode by N2H4 Reduction
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Chengyu Mao Dr. Fan Zuo Dr. Yang Hou Prof. Xianhui Bu Prof. Pingyun Feng 《Angewandte Chemie (International ed. in English)》2014,53(39):10485-10489
A new synthetic method to fabricate Ti3+‐modified, highly stable TiO2 photoanodes for H2O oxidation is reported. With Ti foil as both the conducting substrate and the Ti3+/Ti4+ source, one‐dimensional blue Ti3+/TiO2 crystals were grown by a one‐step hydrothermal reaction. The concentration of Ti3+ was further tuned by N2H4 reduction, leading to a greater photoelectrocatalytic activity, as evidenced by a high photocurrent density of 0.64 mA cm?2 at 1.0 V vs RHE under simulated AM 1.5 G illumination. Electron paramagnetic resonance and Mott–Schottky plots reveal that higher charge‐carrier density owing to N2H4 reduction contributes to the observed improvement. The generality of this synthesis method was demonstrated by its effectiveness in improving the performance of other types of photoanodes. By integrating the advantages of the 1D TiO2 architecture with those of Ti3+ self‐doping, this work provides a versatile tool toward the fabrication of efficient TiO2 photoanodes. 相似文献
18.
本文采用水热法控制制备了具有特殊纳米结构的核-壳和中空多面体二氧化钛, 以进一步提高具有特定暴露面多面体二氧化钛的比表面积, 达到更优异的光催化效果。用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)等技术对所制备特殊结构二氧化钛的物相和微/纳结构进行表征分析, 结果表明所得核-壳和中空结构多面体二氧化钛具有一个类似隧道结构的(001)/(001)洞开的截顶双金字塔型壳层。这两种特殊结构的形成可能是源于配位/弱酸性腐蚀原理的共同作用。用核-壳和中空结构二氧化钛对亚甲基蓝进行光降解实验, 结果表明:所得两种新颖结构二氧化钛的光催化效率得到明显提高, 尤其是在添加过氧化氢条件下。可能原因是:两种特殊结构二氧化钛大比表面积正面作用抵消了(001)晶面消失或减少所产生的副作用, 以及过氧化氢在光催化反应中提供的活性氢氧根自由基使得光辐照二氧化钛产生的电子-空穴对在催化剂表面得到有效分离。 相似文献
19.
Simultaneous growth of 1D/3D-nanorod/nanoflower like structures of TiO2 on fluorine doped tin oxide (FTO) glass substrates has been achieved in one-step hydrothermal process. X-ray diffraction (XRD) pattern confirms the formation of rutile phase whereas enhanced light scattering in 1D/3D nanorod/nanoflower TiO2 photoanode was observed at longer wavelengths of 600–750 nm. Dye sensitized solar cell (DSSC) prepared with 1D/3D-nanorod/nanoflower structures had about 90% increases in efficiency as compared to 1D nanorod like structure. Thus, simultaneous assembly of TiO2 as 1D/3D-nanorod/nanoflower like structure without significant change in their surface oxidation states (Ti3 + and Ti4 +) had better capabilities for light harvesting and efficient electron transportation for improving electrochemical responses of photo-electrode in DSSC to achieve higher sensitivity. 相似文献
20.
R.J. Cava D.W. Murphy S. Zahurak A. Santoro R.S. Roth 《Journal of solid state chemistry》1984,53(1):64-75
The crystal structures of three lithium titanates by neutron diffraction powder profile analysis were determined. The tetragonal anatase form of TiO2 becomes orthorhombic on ambient-temperature lithium insertion to Li0.5TiO2 due to the formation of TiTi bonds. The lithium partially occupies the highly distorted octahedral interstices in the anatase framework in fivefold-coordination with oxygen. Cubic LiTi2O4 formed by heating Li0.5TiO2 anatase has a normal spinel structure with Li in the tetrahedral sites. In Li2Ti2O4 formed by reacting LiTi2O4 spinel with n-BuLi at ambient temperature, the titanium remains in the spinel positions but the lithium is displaced, filling all the available octahedral sites. 相似文献