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1.
TiO2 nanotube arrays sensitized by PbS nanoparticles (TiO2 NTs/PbS) with enhanced visible-light activity were synthesized by a two-step approach including an electrochemical anodization technique followed by an in situ photodeposition approach. The structural investigations indicated that PbS nanoparticles grew uniformly on the walls of the TiO2 NTs. The TiO2 NTs/PbS exhibited more excellent photoelectrochemical properties than that of the TiO2 NTs under visible-light irradiation. The enhanced photoelectrochemical activity of the TiO2 NTs/PbS could be attributed to the improvement of visible-light absorption and charge separation derived from the coupling effect of the PbS nanoparticles and TiO2 NTs. 相似文献
2.
通过二次阳极氧化电化学方法制备纳米孔/纳米管复合结构的阵列型TiO2纳米管(2-step TiO2 NTs),实验证明这种结构的TiO2 NTs对大气中的挥发性有机化合物(volatile organic compounds,VOCs)有着十分优异的降解效果。本文通过气态甲醇的光催化降解来评估比较一次氧化生成的TiO2纳米管(1-step TiO2 NTs)和2-step TiO2 NTs的催化效果。实验结果表明,二次阳极氧化电化学方法所生成的TiO2 NTs的纳米结构对光致电荷的产生有着十分重要的推动作用。之所以2-step TiO2 NTs的纳米孔/纳米管复合结构能够显著提高VOCs的降解效率,是由于这种特殊的结构能够更加有利于电子的传递,同时能够有效地抑制光生电子和空穴的复合。最后,通过实验数据阐述了2-step TiO2 NTs光催化活性的增强机理,这种新结构显示出更小的带隙、更高效的光生电子/空穴分离效率和VOCs降解性能。 相似文献
3.
Fe-modified TiO(2) nanotube arrays (TiO(2) NTs) were prepared by annealing amorphous TiO(2) NTs whose surface was covered with Fe(3+) by a dip-coating procedure, and characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and UV-visible reflectance spectroscopy. The photoelectrochemical properties were evaluated by the photocurrent response and photoelectrocatalytic (PEC) degradation of methylene orange (MO) and 4-chlorophenol in water under visible-light irradiation (λ > 420 nm). The results showed that a Fe-modified TiO(2) NTs electrode exhibited a larger photocurrent response and higher PEC activity for the degradation of organic pollutants than a pure TiO(2) NTs electrode. At a bias potential of 0.4 V, the photocurrent response of a 0.5 M Fe-modified TiO(2) NTs electrode exceeded that of a pure TiO(2) NTs electrode by a factor of about 10, and the PEC degradation rates of MO and 4-chlorophenol on a 0.5 M Fe-modified TiO(2) NTs electrode exceeded those on a pure TiO(2) NTs electrode by a factor of about 2.5. The larger photocurrent response and higher PEC activity of Fe-modified TiO(2) NTs could be attributed to the enhancement of separation of charge-carriers at the external electric field and the extension of the light response range of TiO(2) to the visible-light region with the narrowing of the band gap. 相似文献
4.
Hakan Kiziltaş 《Chemical Engineering Communications》2017,204(8):852-857
Highly ordered titanium nanotubes (TiO2 NTs) photocatalyst was prepared by the anodic oxidation method, and AgS, CdS, and AgS/CdS nanoparticles were doped on the surface of TiO2 NTs by the successive ion adsorption and reaction (SILAR) method. The photocatalysts were characterized by SEM, EDS, XRD, and potentiostat system. The SEM and EDS analyses respectively show that the average outer diameter of prepared photocatalysts is in the range of 50–120?nm, and the presence of Ti, O, Ag, and Cd is successfully proved. The photocatalytic properties of TiO2 NTs and doped TiO2 NTs were studied by measuring the degradation of Methylene Blue (MB) solution. The experimental results show that AgS/CdS/TiO2 photocatalyst exhibited most efficient photocatalytic activity with 340?µA/cm2 photocurrent value. AgS/CdS/TiO2 NTs photocatalyst shows up to 22.20% higher than TiO2 NTs, 16.42% higher than CdS/TiO2 NTs, and 4.3% higher than AgS/TiO2 NTs. 相似文献
5.
《Ceramics International》2016,42(8):9387-9395
Uniformly dispersed Au nanoparticles (NPs) deposited on the surface of highly ordered TiO2 nanotube arrays (Au/TiO2 NTs) were synthesized through a two-step process including anodization method and microwave-assisted chemical reduction route. The investigation indicated that Au NPs grew uniformly on the walls of TiO2 NTs. Au/TiO2 NTs exhibited excellent visible light absorption due to the LSPR effect of Au NPs. Au/TiO2 NTs exhibited much higher photocurrent density and the photoconversion efficiency of Au decorated TiO2 NTs was about 2.05 times greater than that of bare TiO2 NTs. Besides, the PL intensity of Au/TiO2 NTs was much lower than that of TiO2 NTs, revealing a decrease in charge carrier recombination. The prepared Au/TiO2 NTs exhibited superior photoelectrocatalytic activity and stability in the degradation of MB under simulated solar light irradiation. The synergy effect between nanotubular structures of TiO2 and uniformly dispersed Au nanoparticles, as well as the small bias potential and strong interaction between Au and TiO2, facilitated the Au plasmon-induced charge separation and transfer, which lead to highly efficient and stable photoelectrocatalytic activity. 相似文献
6.
《Diamond and Related Materials》2001,10(1):63-67
Large-scale synthesis of multi-walled BN and single-walled B/N-doped C nanotubes (NT) from C nanotube templates was carried out. The NTs were produced through heating of C templates with B2O3 in a flowing N2 atmosphere at 1503–1773 K. The NTs were analyzed by means of a JEM-3000F high-resolution field emission transmission electron microscope operated at 300 kV and equipped with a parallel detection electron energy loss spectrometer. Particular attention was given to the effects of C template morphology, synthesis temperature and metal oxide promoters on the yield and chemical composition of NTs. Ropes consisting of tens of multi-walled BN NTs were synthesized at 1773 K using MoO3 and PbO promoters. Ropes of single-walled B/N-doped C NTs were produced at high yields by synthesis at 1553 K. Packing of NTs in the ropes and nanotube helicities were studied by electron diffraction. B/N-doped C and BN NT morphologies, formation mechanism and atomic structures are discussed in this paper. 相似文献
7.
《Ceramics International》2023,49(4):5893-5904
In this work, nanoflower-like CdS/SnS2/TiO2 NTs ternary heterojunction photocatalysts were synthesized by a hydrothermal method, the relationship between the morphology, microscopic morphology, crystallinity, elemental presence state and hydrogen production performance of the ternary photocatalysts were investigated by SEM, TEM, XRD and XPS, respectively. The photocatalytic performance, electrochemical property and hydrogen production capacity of CdS/SnS2/TiO2 NTs were compared with pure TiO2 NTs, CdS/TiO2 NTs and SnS2/TiO2 NTs. After 2 h of photocatalytic reaction, the removal efficiency of MB wastewater reached 100%, and the photocatalytic efficiencies toward RhB and Cr(VI) removal reached 86.08% and 80.93% after 3 h, respectively. The electron spin resonance (ESR) technique certified the active radical groups that played a role in the catalytic process and further investigated the possible photocatalytic mechanism. Hydrogen production per unit time achieved 97.14 μmol h?1 cm?2, this work provides the new technique to achieve solar energy conversion for hydrogen generation. 相似文献
8.
《Ceramics International》2016,42(6):7192-7202
In this paper, a series of CdS/TiO2 NTs have been synthesized by SILAR method. The as-prepared CdS/TiO2 NTs have been analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive spectrometer (EDS), and ultraviolet–visible (UV–vis). And their photocatalytic activities have been investigated on the degradation of methylene blue under simulated solar light irradiation. XRD results indicate that TiO2 NTs were anatase phase, CdS nanoparticles were hexagonal phase. FESEM results indicate that low deposition concentration can keep the nanotubular structures. UV–vis results indicate that CdS can be used to improve the absorbing capability of TiO2 NTs for visible light, and the content of CdS affects the band gap. Photocatalytic results indicate that CdS nanoparticles are conducive to improve the photocatalytic efficiency of TiO2 NTs, and the highest degradation rate can reach 93.8%. And the photocatalytic mechanism of CdS/TiO2 NTs to methylene blue is also described. 相似文献
9.
Highly ordered tungsten doped TiO2 nanotube arrays (W-TiO2NTs) were prepared in glycerol/fluoride electrolyte solution containing sodium tungstate via the electrochemical oxidation of a Ti substrate. The resulting arrays were characterized by XRD, SEM, and XPS. The 15 mM W-TiO2NTs exhibited better photoelectrochemical activity than the TiO2NTs and W-TiO2NTs fabricated using other W concentrations under Xe illumination. The W ion was successfully introduced into the TiO2 crystal lattice in the W6 + form according to the XPS analysis, which enhanced the photoelectrocatalytic activity of the W-TiO2NTs, as indicated by the efficient removal of Rhodamine B and the production of hydrogen. 相似文献
10.
《Ceramics International》2015,41(7):8735-8741
Highly ordered copper doped TiO2 nanotube arrays (CuTiO2NTs) thin-film were prepared in an aqueous solution containing NH4F and different concentrations of copper nitrate via the electrochemical oxidation of titanium substrates. The resulting nanotubes were characterized by FE-SEM, XRD, XPS and EDX. The CuTiO2NTs showed a tube diameter of 40–90 nm and wall thickness of 20–30 nm. Diffuse reflectance spectra showed a shift toward longer wavelengths relative to pure TiO2 nanotubes (TiO2NTs). The visible light photo-catalytic activity of the CuTiO2NTs electrodes was evaluated by the removal of methylene blue (MB) dye and the production of hydrogen. The results showed that CuTiO2NTs samples exhibited better photo-catalytic activity than the TiO2NTs. This work demonstrated a feasible and simple anodization method to fabricate an effective, reproducible, and inexpensive visible-light-driven photo-catalyst for hydrogen evolution and environmental applications. 相似文献
11.
《Ceramics International》2023,49(19):31679-31690
Luminescent properties of ZnO/TiO2, ZnO/HfO2, and ZnO/ZrO2 core/shell hybrid nanotubes (NTs) with the shell thickness varying between 9 and 40 nm were studied. The hybrid nano-ceramics demonstrated distinct differences in their luminescence performance. The highest UV/VIS ratio and the longest fluorescence lifetime were observed for the ZnO/TiO2 NTs. The behavior was ascribed to resonance energy/charge transfer between TiO2 and ZnO owing to the similar position of conduction and valence band edges, and comparable bandgap energies (Eg) which allowed for a simultaneous excitation of electron-hole pairs in both semiconductors. The difference between the other two core/shell NTs was attributed to the larger bond energy of HfO2 as compared to that of ZrO2 and smaller refractive index of HfO2 as compared to that of ZnO. The results obtained in this work strongly indicate that in the optimal core/shell heterostructure, not only the shell material should form a type-I heterojunction with the ZnO nanostructure but also the excitation energy should be comparable to or larger than the Eg of the coating material. Moreover, the shell material with a high negative formation enthalpy and lower refractive index than that of ZnO would assure an efficient surface passivation and better photon extraction from the emitter. 相似文献
12.
Nanotubes composed of C60 fullerene molecules (C60NTs) were synthesized at ambient pressure and temperature using a modified liquid–liquid interfacial precipitation (LLIP) method in the system of C60–pyridine and isopropyl alcohol (IPA). A marked improvement in the formation of C60NTs was achieved by illuminating the initial C60–pyridine solution with visible light (VIS, 436 nm) and ultraviolet light (UV, 302 nm). It was also found that the growth and diameter of C60NTs are influenced by the combined effect of solvent ratio and incubation temperature. We present a simple approach of fabricating C60NTs designed to optimize rapid growth and to control diameter distributions useful for further discoveries of their chemical and physical properties and in the advancement of their possible applications in nanotechnology. The collected C60NTs were characterized by a variety of analytical techniques including scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and Raman spectroscopy. 相似文献
13.
Xiuzhen Wei Huijuan Wang Guangfeng Zhu Jinyuan Chen Liping Zhu 《Ceramics International》2013,39(4):4009-4016
A series of iron-doped anatase TiO2 nanotubes (Fe/TiO2 NTs) catalysts with iron concentrations ranging from 0.88 to 7.00 wt% were prepared by an ultrasonic-assisted sol-hydrothermal process. The structures and the properties of the fabricated Fe/TiO2 NTs were characterized in detail and photocatalytic activity was examined using a reactive brilliant red X-3B aqueous solution as pollutant under visible light. The lengths of the NTs were determined to range from 20 nm to 100 nm. The incorporation of the iron ions (Fe3+) into the TiO2 nanotubes shifted the photon absorbing zone from the ultraviolet (UV) to the visible wavelengths, reducing the band gap energy from 3.2 to 2.75 eV. The photocatalytic activity of the Fe/TiO2 NTs was 2–4 times higher than the values measured for the pure TiO2 nanotubes. 相似文献
14.
《Ceramics International》2020,46(15):24008-24017
AgCl/AgBr co-sensitizers were prepared on TiO2 nanotube arrays (TiO2 NTs/AgCl/AgBr) by the hydrothermal method. The composition, morphology, optical absorption, photoelectric and photoelectrocatalytic (PEC) performances of TiO2 NTs/AgCl/AgBr were influenced by the concentration ratio of KCl/KBr. The investigation results revealed that the TiO2 NTs/AgCl/AgBr photocatalyst exhibited dramatically strong visible light absorption and outstanding photoelectrochemical capacity. The photoelectrode produced high visible light surface photovoltage (-0.43 V), transient photocurrent (0.47 mA/cm2) and carrier concentration (4.39 × 1020 cm-3). The sample also showed high PEC activity in the organic dye and Cr(VI) removal, and the photocatalytic mechanism and charge carrier transfer path were described based on PEC results. The investigation would offer prospective insight to the sensitization of TiO2 NTs, which would result in extensive attraction in the preparation and application of semiconductor materials as photoelectrodes and photocatalysts with superior photoelectrochemical performances. 相似文献
15.
《应用陶瓷进展》2013,112(6):362-366
Abstract Abstract Thin films of anatase TiO2 nanotube arrays (TiO2 NTs) were prepared in this study. Pt and Ag were coated on the TiO2 NTs films, which intend to increase the photocatalytic activity under ultraviolet-visible (UV-vis) irradiation. The phase and structure of the films were investigated by X-ray diffraction and scanning electron microscopy. Photocatalytic activity was tested by UV-vis absorption spectroscopy and showed that UV-vis light absorption of the films was remarkably improved by coated Ag and Pt by 72% and 183% respectively. The photocatalytic activities of the films towards degraded methyl orange and HCHO were compared and were all found to follow the sequence Pt/TiO2 NTs>Ag/TiO2 NTs>TiO2 NTs. It was also found that the kinetics of HCHO photocatalytic degradation by the films fits the first order reaction model better and has higher efficiency than that of the methyl orange photocatalytic degradation by the same films. 相似文献
16.
Sadia Ameen M. Shaheer Akhtar Young Soon Kim O-Bong Yang Hyung-Shik Shin 《Electrochimica acta》2011,(3):1111
Non-aligned and highly densely aligned ZnO nanotube (NTs), synthesized by low temperature solution method were applied as photoanode materials for the fabrication of efficient dye-sensitized solar cells (DSSCs). The crystalline and the morphological analysis revealed that the grown aligned ZnO NTs possessed a typical hexagonal crystal structure of outer and inner diameter ∼250 nm and ∼100 nm, respectively. ZnO seeding on FTO substrates is an essential step to achieve the aligned ZnO NTs. A DSSC fabricated with aligned ZnO NTs photoanode achieved high solar-to-electricity conversion efficiency of ∼2.2% with short circuit current (JSC) of 5.5 mA/cm2, open circuit voltage (VOC) of 0.65 V and fill factor (FF) of 0.61. Significantly, the aligned ZnO NTs photoanode showed three times improved solar-to-electricity conversion efficiency than DSSC fabricated with non-aligned ZnO NTs. The enhanced performances were credited to the aligned morphology of ZnO NTs which executed the high charge collection and the transfer of electrons at the interfaces of ZnO NTs and electrolyte layer. 相似文献
17.
《Ceramics International》2023,49(4):5977-5985
The efficient TiO2 NTs/Sn3O4 photocatalysts were synthesized by the hydrothermal deposition of Sn3O4 on TiO2 nanotube arrays (TiO2 NTs), and the morphology, microstructure and photocatalytic property were adjusted by changing the alkali kind. The TiO2 NTs/Sn3O4 prepared with NaOH exhibited the outstanding photoelectric conversion and photocatalytic environment remediation/H2 evolution. The methylene blue (MB) dye and Cr(VI) could be removed by the as-prepared photocatalysts under visible light irradiation, and ?O2?/?OH radicals were the main active species for MB photodegradation. Furthermore, the high photocatalytic H2 evolution rate was as high as 6.49 μmol cm?2 h?1. The outstanding photocatalytic activity and stability of TiO2 NTs/Sn3O4 photocatalysts would exhibit attractive prospect in the wastewater remediation and electric energy/hydrogen generation. 相似文献
18.
Changhui Zhao Weizong Lan Huimin Gong Jinglong Bai Rajendran Ramachandran Sheng Liu Fei Wang 《Ceramics International》2018,44(3):2856-2863
Pristine and Pt-decorated copper ferrite nanotubes (Pt-CuFe2O4 NTs, 0.1%, 0.5%, and 1.0%, mole percent) were prepared by a simple electrospinning method. The samples were characterized by X-ray diffraction, scanning electron microscope, and transmission electron microscope. Their gas-sensing properties were evaluated by a commercial CGS-4TPs system. Microscopic images showed that all samples consisted of well-defined nanotubes with diameter of 70?100 nm. Gas-sensing measurements revealed that the Pt-CuFe2O4 NTs had an improved acetone-sensing properties compared with pristine CuFe2O4 NTs. In particular, 0.5% Pt-CuFe2O4 NT-based sensor showed a high response (16.5 at 100 ppm), good selectivity, and long-term stability for acetone at 300 °C. In addition, more Pt dopants would have a greater effect on promoting the sensing properties of the CuFe2O4 NTs at high acetone concentrations. A gas-sensing enhancement mechanism of Pt-CuFe2O4 NT-based sensors was proposed, according to the catalytic oxidation process of acetone molecules, which could be due to the kinetic competition between Pt dopants and CuFe2O4 NTs. 相似文献
19.
20.
Zhiqiang Zhang Congcong Ma Lian He Shijin Zhu Xiaodong Hao Wanyi Xie Wei Zhang Yuxin Zhang 《Nanoscale research letters》2014,9(1):601
In this work, an ultrafast and facile method is developed to synthesize Au(I)-dodecanethiolate nanotubes (Au(I)NTs) with the assistance of glycyl-glycyl-glycine (G-G-G). Transmission electron microscopy (TEM) images reveal that the as-prepared Au(I)NTs can be obtained in a 2-h reaction instead of a previous 24-h reaction and are uniform with a hollow structure and smooth surface by virtue of the G-G-G peptide tubular template. According to structural analysis, a possible preparative mechanism is proposed that the G-G-G peptide could help to curl into tube-like morphology in alkaline situation spontaneously to accelerate the formation of Au(I)NTs. Meanwhile, PVDF-stabilized Au(I)NT-modified glassy carbon electrodes present their promising potential for Hg2+ detection. 相似文献