Controllable synthesis of insertion-type anode materials with beneficial micro-and nanostructures is a promising approach for the synthesis of sodium-ion storage devices with high-reactivity and excellent electrochemi...Controllable synthesis of insertion-type anode materials with beneficial micro-and nanostructures is a promising approach for the synthesis of sodium-ion storage devices with high-reactivity and excellent electrochemical performance.In this study,we developed a sacrificial-templating route to synthesize TiO_(2)@N-doped carbon nanotubes(TiO_(2)@NC-NTs)with excellent electrochemical performance.The asprepared mesoporous TiO_(2)@NC-NTs with tiny nanocrystals of anatase TiO_(2) wrapped in N-doped carbon layers showed a well-defined tube structure with a large specific surface area of 198 m^(2) g^(-1) and a large pore size of~5 nm.The TiO_(2)@NC-NTs delivered high reversible capacities of 158 m A h g^(-1) at 2 C(1 C=335 m A g^(-1))for 2200 cycles and 146 m A h g^(-1) at 5 C for 4000 cycles,as well as an ultrahigh rate capability of up to 40 C with a capacity of 98 m A h g^(-1).Even at a high current density of 10 C,a capacity of 138 m A h g^(-1) could be delivered over 10,000 cycles.Thus,the synthesis of mesoporous TiO_(2)@NC-NTs was demonstrated to be an efficient approach for developing electrode materials with high sodium storage and long cycle life.展开更多
Au nanoparticle-decorated TiO2 nanotube arrays are prepared by a simple method, which is a thermal annealing thin gold film deposited on anodie oxidized TiO2 nanotube arrays. These electron microscope images present t...Au nanoparticle-decorated TiO2 nanotube arrays are prepared by a simple method, which is a thermal annealing thin gold film deposited on anodie oxidized TiO2 nanotube arrays. These electron microscope images present that Au nanoparticles are well dispersed within the wall and on the surface of the XiO2 nanotubes. Meanwhile, the morphologies of Au nanoparticles can be controlled by changing the thickness of the deposited gold film. Associ- ated with the excitation of localized surface plasmon resonances, the prepared Au nanoparticle-decorated TiO2 nanotube arrays could work as visible light responsive photocatalysts to produce a greatly enhanced photocurrent density. By varying the initial gold film thickness, such Au nanoparticle-decorated TiO2 nanotube arrays could be optimized to obtain the highest photocurrent generation efficiency in the visible and UV light regions.展开更多
Highly ordered TiO_2 nanotube arrays(NTAs) on Si substrate possess broad applications due to its high surfaceto-volume ratio and novel functionalities, however, there are still some challenges on facile synthesis. Her...Highly ordered TiO_2 nanotube arrays(NTAs) on Si substrate possess broad applications due to its high surfaceto-volume ratio and novel functionalities, however, there are still some challenges on facile synthesis. Here, we report a simple and cost-effective high-field(90–180V) anodization method to grow highly ordered TiO_2 NTAs on Si substrate,and investigate the effect of anodization time, voltage, and fluoride content on the formation of TiO_2 NTAs. The current density–time curves, recorded during anodization processes, can be used to determine the optimum anodization time. It is found that the growth rate of TiO_2 NTAs is improved significantly under high field, which is nearly 8 times faster than that under low fields(40–60 V). The length and growth rate of the nanotubes are further increased with the increase of fluoride content in the electrolyte.展开更多
The efficiency of photo-electrocatalytic（PECa） devices for the production of solar fuels depends on several limiting factors such as light harvesting, charge recombination and mass transport diffusion. We analyse he...The efficiency of photo-electrocatalytic（PECa） devices for the production of solar fuels depends on several limiting factors such as light harvesting, charge recombination and mass transport diffusion. We analyse here how they influence the performances in PECa cells having a photo-anode based on Au-modified TiOnanotube（TNT） arrays, with the aim of developing design criteria to optimize the photo-anode and the PECa cell configuration for water photo-electrolysis（splitting） and ethanol photo-reforming processes.The TNT samples were prepared by controlled anodic oxidation of Ti foils and then decorated with gold nanoparticles using different techniques to enhance the visible light response through heterojunction and plasmonic effects. The activity tests were made in a gas-phase reactor, as well as in a PECa cell without applied bias. Results were analysed in terms of photo-generated current, Hproduction rate and photoconversion efficiency. Particularly, a solar-to-hydrogen efficiency of 0.83% and a Faradaic efficiency of 91%were obtained without adding sacrificial reagents.展开更多
TiO2 films have been widely applied in photo- voltaic conversion techniques. TiO2 nanotube arrays （TiO2 NAs） can be grown directly on the surface of metal Ti by the anodic oxidation method. Bi2S3 and PbS nanoparticl...TiO2 films have been widely applied in photo- voltaic conversion techniques. TiO2 nanotube arrays （TiO2 NAs） can be grown directly on the surface of metal Ti by the anodic oxidation method. Bi2S3 and PbS nanoparticles （NPs） were firstly co-sensitized on TiOa NAs （denoted as PbS/Bi2S3（n）/TiO2 NAs） by a two-step process containing hydrothermal and sonication-assisted SILAR method. When the concentration of Bi3＋ is 5 mmol/L, the best photoelectrical performance was obtained under simulated solar irradiation. The short-circuit photocurrent （Jsc） and photoconversion efficiency （η） of PbS/Bi2S3（5）/TiO2 NAs electrode were 4.70 mA/cm and 1.13 %, respectively.展开更多
We report the development of a novel visible response BiVO_4/TiO_2(N_2) nanotubes photoanode for photoelectrocatalytic applications. The nitrogen-treated TiO_2 nanotube shows a high carrier concentration rate, thus re...We report the development of a novel visible response BiVO_4/TiO_2(N_2) nanotubes photoanode for photoelectrocatalytic applications. The nitrogen-treated TiO_2 nanotube shows a high carrier concentration rate, thus resulting in a high efficient charge transportation and low electron–hole recombination in the TiO_2–BiVO_4. Therefore, the BiVO_4/TiO_2(N_2) NTs photoanode enabled with a significantly enhanced photocurrent of 2.73 mA cm^(-2)(at 1 V vs. Ag/Ag Cl) and a degradation efficiency in the oxidation of dyes under visible light. Field emission scanning electron microscopy, X-ray diffractometry, energy-dispersive X-ray spectrometer, and UV–Vis absorption spectrum were conducted to characterize the photoanode and demonstrated the presence of both metal oxides as a junction composite.展开更多
Well-ordered TiO_2 nanotube arrays(TNTAs)decorated with graphitic carbon nitride(g-C_3N_4) were fabricated by anodic oxidization and calcination process.First, TNTAs were prepared via the anodic oxidation of Ti foil i...Well-ordered TiO_2 nanotube arrays(TNTAs)decorated with graphitic carbon nitride(g-C_3N_4) were fabricated by anodic oxidization and calcination process.First, TNTAs were prepared via the anodic oxidation of Ti foil in glycerol solution containing fluorinion and 20%deionized water. Subsequently, g-C_3N_4 film was hydrothermally grown on TNTAs via the hydrogen-bonded cyanuric acid melamine supramolecular complex. The results showed that g-C_3N_4 was successfully decorated on the TNTAs and the g-C_3N_4/TNTAs served as an efficient and stable photoanode for photoelectrochemical water splitting. The facile deposition method enables the fabrication of efficient and low-cost photoanodes for renewable energy applications.展开更多
Copper and titanium remain relatively plentiful in earth crust.Therefore,using them in solar energy conversion technologies are of significant interest.In this work,cuprous oxide（Cu2O）-modified short TiO2 nanotube a...Copper and titanium remain relatively plentiful in earth crust.Therefore,using them in solar energy conversion technologies are of significant interest.In this work,cuprous oxide（Cu2O）-modified short TiO2 nanotube array electrode was prepared based on the following two design ideas:first,the short titania nanotubes obtained from sonoelectrochemical anodization possess excellent charge separation and transportation properties as well as desirable mechanical stability;second,the sonoelectrochemical deposition technique favours the improvement in the combination between Cu2O and TiO2 nanotubes,and favours the dispersion of Cu2O particles.UV-Vis absorption and photo-electronchemical measurements proved that the Cu2O coating extended the visible spectrum absorption and the solar spectrum-induced photocurrent response.Under AM1.5 irradiation,the photocurrent density of the composite electrode（i.e.sonoelectrochemical deposition for 5 min） was more than 4.75 times as high as the pure nanotube electrode.Comparing the photoactivity of the Cu2O/TiO2 electrode obtained using sonoelectrochemical deposition with others that synthesized using plain electrochemical deposition,the photocurrent density of the former electrode was 2.2 times higher than that of the latter when biased at 1.0 V（vs.Ag/AgCl）.The reproducible photocurrent response under intermittent illumination demonstrated the excellent stability of the composite electrode.Such kind of composite electrode material will have many potential applications in solar cell and other fields.展开更多
The highly ordered TiO2 nanotubes (NTs) were fabricated by the anodic oxidation method. Their morphology, structure and crystalline phase were characterized by scanning electron microscopy (SEM) and X-ray diffractomet...The highly ordered TiO2 nanotubes (NTs) were fabricated by the anodic oxidation method. Their morphology, structure and crystalline phase were characterized by scanning electron microscopy (SEM) and X-ray diffractometer (XRD). The effects of morphology, specific surface area, pore structures and photo catalytic activity of the TiO2 NTs were investigated. UV-vis spectra analysis showed that its light absorption had been extended to the visible light range. The photocatalytic activity of the as-prepared samples was evaluated by photocatalytic oxidation of gaseous HCHO and MB aqueous solution. The samples had better adhesion strength in the dark and showed a higher photocatalytic activity than nanoparticles. Especially, with ultraviolet light pretreatment, the nanotubes exhibited more stable active for photocatalytic decomposition and the photodecomposition rate remained at high level after 3 cycles of the photocatalysis experiment. Thus, how the number of surface active group center dot OH increased and the mechanism for the great improvement for the photocatalytic activity are discussed. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.展开更多
The paper reports the fabrication of Zn-doped TiO_2 nanotubes(Zn-TONT)/ZnO nanoflakes heterostructure for the first time,which shows improved performance as a photoanode in dye-sensitized solar cell(DSSC).The layered ...The paper reports the fabrication of Zn-doped TiO_2 nanotubes(Zn-TONT)/ZnO nanoflakes heterostructure for the first time,which shows improved performance as a photoanode in dye-sensitized solar cell(DSSC).The layered structure of this novel nanoporous structure has been analyzed unambiguously by Rutherford backscattering spectroscopy,scanning electron microscopy,and X-ray diffractometer.The cell using the heterostructure as photoanode manifests an enhancement of about an order in the magnitude of the short circuit current and a seven-fold increase in efficiency,over pure TiO_2 photoanodes.Characterizations further reveal that the Zn-TONT is preferentially oriented in [001] direction and there is a Ti metal-depleted interface layer which leads to better band alignment in DSSC.展开更多
An inverted structure of polymer solar cells based on Poly（3-hexylthiophene）（P3HT）：[6-6] Phenyl-（6） butyric acid methyl ester （PCBM） with using thin films of TiO2 nanotubes and nanoparticles as an efficient c...An inverted structure of polymer solar cells based on Poly（3-hexylthiophene）（P3HT）：[6-6] Phenyl-（6） butyric acid methyl ester （PCBM） with using thin films of TiO2 nanotubes and nanoparticles as an efficient cathode buffer layer is developed. A total of three cells employing TiO2 thin films with different thickness values are fabricated. Two cells use layers of TiO2 nanotubes prepared via self-organized electrochemical-anodizing leading to thickness values of 203 and 423.7 nm, while the other cell uses only a simple sol-gel synthesized TiO2 thin film of nanoparticles with a thickness of 100 nm as electron transport layer. Experimental results demonstrate that TiO2 nanotubes with these thickness values are inefficient as the power conversion efficiency of the cell using 100-nm TiO2 thin film is 1.55%, which is more than the best power conversion efficiency of other cells. This can be a result of the weakness of the electrochemical anodizing method to grow nanotubes with lower thickness values. In fact as the TiO2 nanotubes grow in length the series resistance （Rs） between the active polymer layer and electron transport layer increases, meanwhile the fill factor of cells falls dramatically which finally downgrades the power conversion efficiency of the cells as the fill factor falls.展开更多
Highly ordered TiO2 nanotube array （TNA） films are fabricated by using an anodic oxidation method. Au nanoparticles （NPs） films are decorated onto the top of TNA films with the aid of ion-sputtering and thermal an...Highly ordered TiO2 nanotube array （TNA） films are fabricated by using an anodic oxidation method. Au nanoparticles （NPs） films are decorated onto the top of TNA films with the aid of ion-sputtering and thermal annealing. An enhanced photocatalytic activity under ultraviolet C （UVC, 266 nm） light irradiation is obtained compared with that of the pristine TNA, which is shown by the steady-state photoluminescence （PL） spectra. Furthermore, a distinct blue shift in the nanosecond time-resolved transient photoluminescence （NTRT-PL） spectra is observed. Such a phenomenon could be well explained by considering the competition between the surface photocatalytic process and the recombination of the photo-generated carriers. The enhanced UV photocatalytic activities of the Au-TNA composite are evaluated through photo-degradation of methyl orange （MO） in an aqueous solution with ultraviolet-visible absorption spectrometry. Our current work may provide a simple strategy to synthesize defect-related composite photocatalytic devices.展开更多
A series of titania nanoparticles and nanotubes deposited with various quantities of bismuth（Bi） were prepared via sol-gel and hydrothermal methods, respectively. They were then characterized using X-ray diffraction...A series of titania nanoparticles and nanotubes deposited with various quantities of bismuth（Bi） were prepared via sol-gel and hydrothermal methods, respectively. They were then characterized using X-ray diffraction spectroscopy（XRD）, X-ray photo electron spectroscopy（XPS）, UV–Vis diffused reflectance spectra（DRS）, photoluminescence spectra（PLS）, transmission electron microscopy（TEM）, energy dispersive analysis of X-rays（EDAX）, and BET surface analysis. These catalysts were employed for the photocatalytic production of hydrogen from a mixture of pure water and glycerol under solar light irradiation. The presence of the Bispecies was found to play a vital role in enhancing activity while minimizing electron hole recombination（relative to bare TiO）. The nanotubes exhibited better activity than the nanoparticles of Bi-deposited TiO, showing the significance of the morphology; however, photocatalytic activity is predominantly dependent on the deposition of bismuth. The activity increased by approximately an order of magnitude at the optimum concentration of Bi deposited over TiO（2 wt%）. The presence of the Bispecies played a vital role in minimizing electron hole recombination, resulting in higher activity compared to bare TiO.展开更多
TiOz nanotubes （TiO2-NTs） were synthesized by the hydrothermal method. Co and Mo active components were supported on a series of the as-prepared TiO2-NTs samples which were calcined at different temperatures. The ef...TiOz nanotubes （TiO2-NTs） were synthesized by the hydrothermal method. Co and Mo active components were supported on a series of the as-prepared TiO2-NTs samples which were calcined at different temperatures. The effects of support calcination temperature of CoMo/TiOz- NTs catalysts on their catalytic performance were investigated for selective hydrodesulfurization （HDS）. The samples were characterized by means of the scanning electron microscopy （SEM）, the transmission electron microscopy （TEM）, N2 adsorption-desorption, X-ray diffraction （XRD）, Raman spectroscopy and H2 temperature-programmed reduction （Hz-TPR）. The experimental results revealed that TiOz-NTs support calcined under 500℃ can maintain the nanotubular structure with higher surface area and pore volume. Meanwhile, the obtained supported CoMo/TiO2-NTs catalysts exhibited weak metal-support interaction, more octahedral Mo6＋ species and high catalytic performance in selective HDS.展开更多
TiO2 nanotubes（TNTs） with nickel sulfide（NiS） co-catalyst were prepared by a simple solvothermal method and characterized by X-ray diffraction, transmission electron microscope, N2-physisorption, UV–vis diffuse r...TiO2 nanotubes（TNTs） with nickel sulfide（NiS） co-catalyst were prepared by a simple solvothermal method and characterized by X-ray diffraction, transmission electron microscope, N2-physisorption, UV–vis diffuse reflectance spectroscopy and photoluminescence spectroscopy. Loading NiS nano-clusters can significantly enhance the photocatalytic H2 evolution performance of TNTs. The optimum NiS loading content was found to be 8 wt% and the corresponding hydrogen production rate is ca. 7486 μmol/h/g, being about 79 times higher than that of pure TNTs. This enhancement of photocatalytic H2 evolution was attributed to the synergistic effect between NiS and TNTs.展开更多
TiO_2 nanotubes(TNTs) have drawn tremendous attention owing to their unique architectural and physical properties. Anodizing of titanium foil has proven to be the most efficient method to fabricate well-aligned TNTs,w...TiO_2 nanotubes(TNTs) have drawn tremendous attention owing to their unique architectural and physical properties. Anodizing of titanium foil has proven to be the most efficient method to fabricate well-aligned TNTs,which, however, usually produces amorphous TNTs and needs further thermal annealing. Recently, a water-assisted crystallization strategy has been proposed and investigated by both science and engineering communities. This method is very efficient and energy saving, and it circumvents the drawbacks of thermal sintering approach. In this paper, we review the recent research progress in this kind of lowtemperature crystallization approach. Here, various synthetic methods are summarized, and the mechanisms of the amorphous–crystalline transformation are analyzed. The fundamental properties and applications of the low-temperature products are also discussed. Furthermore, it is proved that the water-assisted crystallization approach is not only applicable to TNTs but also to crystallizing other metal oxides.展开更多
The application of TiO2-based devices is mainly dependent on their crystalline structure, morphology, size, and exposed facets. Two kinds of TiO2 with different structures, namely TiO2 pompons and TiO2 nanotubes, have...The application of TiO2-based devices is mainly dependent on their crystalline structure, morphology, size, and exposed facets. Two kinds of TiO2 with different structures, namely TiO2 pompons and TiO2 nanotubes, have been prepared by the hydrothermal method. TiO2 with different structures is characterized by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and Brunauer Emmett-Teller （BET） surface area analysis. Solar cells based on poly（3-hexylthiophene） （P3HT） and TiO2 with different structures are fabricated. In the device ITO/TiO2/P3HT/Au, the P3HT is designed to act as the electron donor, and TiO2 pompons and TiO2 nanotubes act as the electron acceptor. The effects of the TiO2 structure on the performance of hybrid heterojunction solar cells are investigated. The device with TiO2 pompons has an open circuit voltage （Voc） of 0.51 V, a short circuit current （Jsc） of 0.21 mA/cm2, and a fill factor （FF） of 28.3%. Another device with TiO2 nanotubes has a Voc of 0.5 V, Jsc of 0.27 mA/cm2, and FF of 28.4%. The results indicate that the TiO2 nanotubes with a unidimensional structure have better carrier transport and light absorption properties than TiO2 pompons. Consequently, the solar cell based on TiO2 nanotubes has a better performance.展开更多
基金the financial support provided by internal reseach funding of Khalifa University of Science and Technology,United Arab Emirates(Grant No.CIRA-2018-16)。
文摘Controllable synthesis of insertion-type anode materials with beneficial micro-and nanostructures is a promising approach for the synthesis of sodium-ion storage devices with high-reactivity and excellent electrochemical performance.In this study,we developed a sacrificial-templating route to synthesize TiO_(2)@N-doped carbon nanotubes(TiO_(2)@NC-NTs)with excellent electrochemical performance.The asprepared mesoporous TiO_(2)@NC-NTs with tiny nanocrystals of anatase TiO_(2) wrapped in N-doped carbon layers showed a well-defined tube structure with a large specific surface area of 198 m^(2) g^(-1) and a large pore size of~5 nm.The TiO_(2)@NC-NTs delivered high reversible capacities of 158 m A h g^(-1) at 2 C(1 C=335 m A g^(-1))for 2200 cycles and 146 m A h g^(-1) at 5 C for 4000 cycles,as well as an ultrahigh rate capability of up to 40 C with a capacity of 98 m A h g^(-1).Even at a high current density of 10 C,a capacity of 138 m A h g^(-1) could be delivered over 10,000 cycles.Thus,the synthesis of mesoporous TiO_(2)@NC-NTs was demonstrated to be an efficient approach for developing electrode materials with high sodium storage and long cycle life.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11474215 and 21204058the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Au nanoparticle-decorated TiO2 nanotube arrays are prepared by a simple method, which is a thermal annealing thin gold film deposited on anodie oxidized TiO2 nanotube arrays. These electron microscope images present that Au nanoparticles are well dispersed within the wall and on the surface of the XiO2 nanotubes. Meanwhile, the morphologies of Au nanoparticles can be controlled by changing the thickness of the deposited gold film. Associ- ated with the excitation of localized surface plasmon resonances, the prepared Au nanoparticle-decorated TiO2 nanotube arrays could work as visible light responsive photocatalysts to produce a greatly enhanced photocurrent density. By varying the initial gold film thickness, such Au nanoparticle-decorated TiO2 nanotube arrays could be optimized to obtain the highest photocurrent generation efficiency in the visible and UV light regions.
基金supported by National 863 Program 2011AA050518the Natural Science Foundation of China(Grant Nos.11174197,11574203,and 61234005)
文摘Highly ordered TiO_2 nanotube arrays(NTAs) on Si substrate possess broad applications due to its high surfaceto-volume ratio and novel functionalities, however, there are still some challenges on facile synthesis. Here, we report a simple and cost-effective high-field(90–180V) anodization method to grow highly ordered TiO_2 NTAs on Si substrate,and investigate the effect of anodization time, voltage, and fluoride content on the formation of TiO_2 NTAs. The current density–time curves, recorded during anodization processes, can be used to determine the optimum anodization time. It is found that the growth rate of TiO_2 NTAs is improved significantly under high field, which is nearly 8 times faster than that under low fields(40–60 V). The length and growth rate of the nanotubes are further increased with the increase of fluoride content in the electrolyte.
基金The TERRA(Tandem Electrocatalytic Reactor for energy/Resource efficiency and process intensification,H2020 project 677471)Eco~2CO_2(Eco-friendly biorefinery fine chemicals from CO_2 photo-catalytic reduction,FP7 project 309701)
文摘The efficiency of photo-electrocatalytic（PECa） devices for the production of solar fuels depends on several limiting factors such as light harvesting, charge recombination and mass transport diffusion. We analyse here how they influence the performances in PECa cells having a photo-anode based on Au-modified TiOnanotube（TNT） arrays, with the aim of developing design criteria to optimize the photo-anode and the PECa cell configuration for water photo-electrolysis（splitting） and ethanol photo-reforming processes.The TNT samples were prepared by controlled anodic oxidation of Ti foils and then decorated with gold nanoparticles using different techniques to enhance the visible light response through heterojunction and plasmonic effects. The activity tests were made in a gas-phase reactor, as well as in a PECa cell without applied bias. Results were analysed in terms of photo-generated current, Hproduction rate and photoconversion efficiency. Particularly, a solar-to-hydrogen efficiency of 0.83% and a Faradaic efficiency of 91%were obtained without adding sacrificial reagents.
基金supported by Program of International S&T Cooperation(2013 DFA51050)National Magnetic Confinement Fusion Science Program(2013GB110001)+2 种基金the 863Program(2014AA032701)the National Natural Science Foundation of China(11405138,51302231)the Western Superconducting Technologies Co.,Ltd
文摘TiO2 films have been widely applied in photo- voltaic conversion techniques. TiO2 nanotube arrays （TiO2 NAs） can be grown directly on the surface of metal Ti by the anodic oxidation method. Bi2S3 and PbS nanoparticles （NPs） were firstly co-sensitized on TiOa NAs （denoted as PbS/Bi2S3（n）/TiO2 NAs） by a two-step process containing hydrothermal and sonication-assisted SILAR method. When the concentration of Bi3＋ is 5 mmol/L, the best photoelectrical performance was obtained under simulated solar irradiation. The short-circuit photocurrent （Jsc） and photoconversion efficiency （η） of PbS/Bi2S3（5）/TiO2 NAs electrode were 4.70 mA/cm and 1.13 %, respectively.
基金the National Nature Science Foundation of China(21507085,21576162)Shanghai Sailing Program of China(14YF1401500)for financial support
文摘We report the development of a novel visible response BiVO_4/TiO_2(N_2) nanotubes photoanode for photoelectrocatalytic applications. The nitrogen-treated TiO_2 nanotube shows a high carrier concentration rate, thus resulting in a high efficient charge transportation and low electron–hole recombination in the TiO_2–BiVO_4. Therefore, the BiVO_4/TiO_2(N_2) NTs photoanode enabled with a significantly enhanced photocurrent of 2.73 mA cm^(-2)(at 1 V vs. Ag/Ag Cl) and a degradation efficiency in the oxidation of dyes under visible light. Field emission scanning electron microscopy, X-ray diffractometry, energy-dispersive X-ray spectrometer, and UV–Vis absorption spectrum were conducted to characterize the photoanode and demonstrated the presence of both metal oxides as a junction composite.
基金financial support from the National Natural Science Foundation of China (Nos. 51702025, 51574047)Natural Science Foundation of Jiangsu Province (Nos. BK20160277, BK20150259)
文摘Well-ordered TiO_2 nanotube arrays(TNTAs)decorated with graphitic carbon nitride(g-C_3N_4) were fabricated by anodic oxidization and calcination process.First, TNTAs were prepared via the anodic oxidation of Ti foil in glycerol solution containing fluorinion and 20%deionized water. Subsequently, g-C_3N_4 film was hydrothermally grown on TNTAs via the hydrogen-bonded cyanuric acid melamine supramolecular complex. The results showed that g-C_3N_4 was successfully decorated on the TNTAs and the g-C_3N_4/TNTAs served as an efficient and stable photoanode for photoelectrochemical water splitting. The facile deposition method enables the fabrication of efficient and low-cost photoanodes for renewable energy applications.
基金the State Key Development Program for Basic Research of China (Grant No.2009CB220004)the Shanghai Basic Research Key Project (08JC1411300,0952nm01800)+1 种基金the National High Technology Research and Development Program of China (Grant No.2009 AA063003)Shanghai Tongji Gao Tingyao Environmental Science and Technology Development Foundation for financial support
文摘Copper and titanium remain relatively plentiful in earth crust.Therefore,using them in solar energy conversion technologies are of significant interest.In this work,cuprous oxide（Cu2O）-modified short TiO2 nanotube array electrode was prepared based on the following two design ideas:first,the short titania nanotubes obtained from sonoelectrochemical anodization possess excellent charge separation and transportation properties as well as desirable mechanical stability;second,the sonoelectrochemical deposition technique favours the improvement in the combination between Cu2O and TiO2 nanotubes,and favours the dispersion of Cu2O particles.UV-Vis absorption and photo-electronchemical measurements proved that the Cu2O coating extended the visible spectrum absorption and the solar spectrum-induced photocurrent response.Under AM1.5 irradiation,the photocurrent density of the composite electrode（i.e.sonoelectrochemical deposition for 5 min） was more than 4.75 times as high as the pure nanotube electrode.Comparing the photoactivity of the Cu2O/TiO2 electrode obtained using sonoelectrochemical deposition with others that synthesized using plain electrochemical deposition,the photocurrent density of the former electrode was 2.2 times higher than that of the latter when biased at 1.0 V（vs.Ag/AgCl）.The reproducible photocurrent response under intermittent illumination demonstrated the excellent stability of the composite electrode.Such kind of composite electrode material will have many potential applications in solar cell and other fields.
基金financial support from Tianjin Science and Technology Support Plan Key Projects(NO.12ZCZDJC35600)
文摘The highly ordered TiO2 nanotubes (NTs) were fabricated by the anodic oxidation method. Their morphology, structure and crystalline phase were characterized by scanning electron microscopy (SEM) and X-ray diffractometer (XRD). The effects of morphology, specific surface area, pore structures and photo catalytic activity of the TiO2 NTs were investigated. UV-vis spectra analysis showed that its light absorption had been extended to the visible light range. The photocatalytic activity of the as-prepared samples was evaluated by photocatalytic oxidation of gaseous HCHO and MB aqueous solution. The samples had better adhesion strength in the dark and showed a higher photocatalytic activity than nanoparticles. Especially, with ultraviolet light pretreatment, the nanotubes exhibited more stable active for photocatalytic decomposition and the photodecomposition rate remained at high level after 3 cycles of the photocatalysis experiment. Thus, how the number of surface active group center dot OH increased and the mechanism for the great improvement for the photocatalytic activity are discussed. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.
基金UGC-DAE CSR,Indore,for funding through a collaborative project and SAIF IIT Bombay for the help with SEMsupported by the Michigan Space Grant Consortium+1 种基金by Hope CollegeDAE-BRNS for funding the preliminary works
文摘The paper reports the fabrication of Zn-doped TiO_2 nanotubes(Zn-TONT)/ZnO nanoflakes heterostructure for the first time,which shows improved performance as a photoanode in dye-sensitized solar cell(DSSC).The layered structure of this novel nanoporous structure has been analyzed unambiguously by Rutherford backscattering spectroscopy,scanning electron microscopy,and X-ray diffractometer.The cell using the heterostructure as photoanode manifests an enhancement of about an order in the magnitude of the short circuit current and a seven-fold increase in efficiency,over pure TiO_2 photoanodes.Characterizations further reveal that the Zn-TONT is preferentially oriented in [001] direction and there is a Ti metal-depleted interface layer which leads to better band alignment in DSSC.
文摘An inverted structure of polymer solar cells based on Poly（3-hexylthiophene）（P3HT）：[6-6] Phenyl-（6） butyric acid methyl ester （PCBM） with using thin films of TiO2 nanotubes and nanoparticles as an efficient cathode buffer layer is developed. A total of three cells employing TiO2 thin films with different thickness values are fabricated. Two cells use layers of TiO2 nanotubes prepared via self-organized electrochemical-anodizing leading to thickness values of 203 and 423.7 nm, while the other cell uses only a simple sol-gel synthesized TiO2 thin film of nanoparticles with a thickness of 100 nm as electron transport layer. Experimental results demonstrate that TiO2 nanotubes with these thickness values are inefficient as the power conversion efficiency of the cell using 100-nm TiO2 thin film is 1.55%, which is more than the best power conversion efficiency of other cells. This can be a result of the weakness of the electrochemical anodizing method to grow nanotubes with lower thickness values. In fact as the TiO2 nanotubes grow in length the series resistance （Rs） between the active polymer layer and electron transport layer increases, meanwhile the fill factor of cells falls dramatically which finally downgrades the power conversion efficiency of the cells as the fill factor falls.
基金supported by the National Natural Science Foundation of China(Grant No.11274082)the Shandong Excellent Young Scientist Research Award Fund Project,China(Grant No.BS2011CL002)
文摘Highly ordered TiO2 nanotube array （TNA） films are fabricated by using an anodic oxidation method. Au nanoparticles （NPs） films are decorated onto the top of TNA films with the aid of ion-sputtering and thermal annealing. An enhanced photocatalytic activity under ultraviolet C （UVC, 266 nm） light irradiation is obtained compared with that of the pristine TNA, which is shown by the steady-state photoluminescence （PL） spectra. Furthermore, a distinct blue shift in the nanosecond time-resolved transient photoluminescence （NTRT-PL） spectra is observed. Such a phenomenon could be well explained by considering the competition between the surface photocatalytic process and the recombination of the photo-generated carriers. The enhanced UV photocatalytic activities of the Au-TNA composite are evaluated through photo-degradation of methyl orange （MO） in an aqueous solution with ultraviolet-visible absorption spectrometry. Our current work may provide a simple strategy to synthesize defect-related composite photocatalytic devices.
基金support from a National Research Foundation of Korea(NRF)grant funded by the Ministry of Science,ICT&Future Planning(No.2016R1E1A1A01940995)
文摘A series of titania nanoparticles and nanotubes deposited with various quantities of bismuth（Bi） were prepared via sol-gel and hydrothermal methods, respectively. They were then characterized using X-ray diffraction spectroscopy（XRD）, X-ray photo electron spectroscopy（XPS）, UV–Vis diffused reflectance spectra（DRS）, photoluminescence spectra（PLS）, transmission electron microscopy（TEM）, energy dispersive analysis of X-rays（EDAX）, and BET surface analysis. These catalysts were employed for the photocatalytic production of hydrogen from a mixture of pure water and glycerol under solar light irradiation. The presence of the Bispecies was found to play a vital role in enhancing activity while minimizing electron hole recombination（relative to bare TiO）. The nanotubes exhibited better activity than the nanoparticles of Bi-deposited TiO, showing the significance of the morphology; however, photocatalytic activity is predominantly dependent on the deposition of bismuth. The activity increased by approximately an order of magnitude at the optimum concentration of Bi deposited over TiO（2 wt%）. The presence of the Bispecies played a vital role in minimizing electron hole recombination, resulting in higher activity compared to bare TiO.
文摘TiOz nanotubes （TiO2-NTs） were synthesized by the hydrothermal method. Co and Mo active components were supported on a series of the as-prepared TiO2-NTs samples which were calcined at different temperatures. The effects of support calcination temperature of CoMo/TiOz- NTs catalysts on their catalytic performance were investigated for selective hydrodesulfurization （HDS）. The samples were characterized by means of the scanning electron microscopy （SEM）, the transmission electron microscopy （TEM）, N2 adsorption-desorption, X-ray diffraction （XRD）, Raman spectroscopy and H2 temperature-programmed reduction （Hz-TPR）. The experimental results revealed that TiOz-NTs support calcined under 500℃ can maintain the nanotubular structure with higher surface area and pore volume. Meanwhile, the obtained supported CoMo/TiO2-NTs catalysts exhibited weak metal-support interaction, more octahedral Mo6＋ species and high catalytic performance in selective HDS.
基金supported by the National Natural Science Foundation of China(no.21376102)the Natural Science Foundation of Guangdong Province,China(no.S2013010012199)
文摘TiO2 nanotubes（TNTs） with nickel sulfide（NiS） co-catalyst were prepared by a simple solvothermal method and characterized by X-ray diffraction, transmission electron microscope, N2-physisorption, UV–vis diffuse reflectance spectroscopy and photoluminescence spectroscopy. Loading NiS nano-clusters can significantly enhance the photocatalytic H2 evolution performance of TNTs. The optimum NiS loading content was found to be 8 wt% and the corresponding hydrogen production rate is ca. 7486 μmol/h/g, being about 79 times higher than that of pure TNTs. This enhancement of photocatalytic H2 evolution was attributed to the synergistic effect between NiS and TNTs.
基金financially supported by the National R&D Program of China under No.2017YFA0207400National Key Research and Development Plan under No.2016YFA0300801National Natural Science Foundation of China under Nos.51502033,61571079,61131005 and 51572042
文摘TiO_2 nanotubes(TNTs) have drawn tremendous attention owing to their unique architectural and physical properties. Anodizing of titanium foil has proven to be the most efficient method to fabricate well-aligned TNTs,which, however, usually produces amorphous TNTs and needs further thermal annealing. Recently, a water-assisted crystallization strategy has been proposed and investigated by both science and engineering communities. This method is very efficient and energy saving, and it circumvents the drawbacks of thermal sintering approach. In this paper, we review the recent research progress in this kind of lowtemperature crystallization approach. Here, various synthetic methods are summarized, and the mechanisms of the amorphous–crystalline transformation are analyzed. The fundamental properties and applications of the low-temperature products are also discussed. Furthermore, it is proved that the water-assisted crystallization approach is not only applicable to TNTs but also to crystallizing other metal oxides.
基金Project supported by the Ministry of Science and Technology of China (Grant No. 2011CB932802)the National Natural Science Foundation of China (Grant No. 60978060)the Beijing Municipal Science & Technology Commission,China (Grant No. Z090803044009001)
文摘The application of TiO2-based devices is mainly dependent on their crystalline structure, morphology, size, and exposed facets. Two kinds of TiO2 with different structures, namely TiO2 pompons and TiO2 nanotubes, have been prepared by the hydrothermal method. TiO2 with different structures is characterized by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and Brunauer Emmett-Teller （BET） surface area analysis. Solar cells based on poly（3-hexylthiophene） （P3HT） and TiO2 with different structures are fabricated. In the device ITO/TiO2/P3HT/Au, the P3HT is designed to act as the electron donor, and TiO2 pompons and TiO2 nanotubes act as the electron acceptor. The effects of the TiO2 structure on the performance of hybrid heterojunction solar cells are investigated. The device with TiO2 pompons has an open circuit voltage （Voc） of 0.51 V, a short circuit current （Jsc） of 0.21 mA/cm2, and a fill factor （FF） of 28.3%. Another device with TiO2 nanotubes has a Voc of 0.5 V, Jsc of 0.27 mA/cm2, and FF of 28.4%. The results indicate that the TiO2 nanotubes with a unidimensional structure have better carrier transport and light absorption properties than TiO2 pompons. Consequently, the solar cell based on TiO2 nanotubes has a better performance.
