共查询到20条相似文献,搜索用时 171 毫秒
1.
Enzhou Liu Limin Kang Feng Wu Tao Sun Xiaoyun Hu Yuhao Yang Hanchen Liu Jun Fan 《Plasmonics (Norwell, Mass.)》2014,9(1):61-70
Ag-loaded TiO2 (Ag/TiO2) nanocomposites were prepared by microwave-assisted chemical reduction method using tetrabutyl titanate as the Ti source. The prepared samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N2 adsorption–desorption isotherms, UV–vis absorption spectrum, X-ray photoelectron spectrum, photoluminescence spectrum, and Raman scattering spectrum, respectively. Results revealed that Ag nanoparticles (NPs) were successfully deposited on TiO2 by reduction of Ag+, and the visible light absorption and Raman scattering of TiO2 were enhanced by Ag NPs based on its surface plasmon resonance effect. Besides, Ag NPs could also effectively restrain the recombination of photogenerated electrons and holes with a longer luminescence life time. In addition, photocatalytic reduction of CO2 with H2O on the composites was conducted to obtain methanol. Experimental results indicated that Ag-loaded TiO2 had better photocatalytic activity than pure TiO2 due to the synergistic effect between UV light excitation and surface plasmon resonance enhancement, and 2.5 % Ag/TiO2 exhibited the best activity; the corresponding energy efficiency was about 0.5 % and methanol yield was 405.2 μmol/g-cat, which was 9.4 times higher than that of pure TiO2. Additionally, an excitation enhancement synergistic mechanism was proposed to explain the experimental results of photocatalytic reduction of CO2 under different reaction conditions. 相似文献
2.
Feng Wu Xiaoyun Hu Jun Fan Enzhou Liu Tao Sun Limin Kang Wenqian Hou Changjun Zhu Hanchen Liu 《Plasmonics (Norwell, Mass.)》2013,8(2):501-508
TiO2 nanotube arrays (TiO2 NTs) were fabricated by anodic oxidation and then Ag nanoparticles (Ag NPs) were assembled in TiO2 NTs (Ag/TiO2 NTs) by microwave-assisted chemical reduction. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), photoluminescence spectrum (PL), UV–vis absorption spectrum (UV–vis), and Raman spectrum, respectively. The results showed that Ag NPs were well dispersed on the surface of TiO2 NTs with metallic state. The surface plasmon resonance (SPR) effect of Ag NPs could extend the visible light response and enhance the absorption capacity of TiO2. Furthermore, Ag NPs could also restrain the recombination of photo-generated electron–hole pairs of TiO2 NTs efficiently. The methylene blue photodegradation experiment proved that the SPR phenomenon had an effect on photoreaction enhancement. The results of photocatalytic water splitting indicated that Ag/TiO2 NTs samples had better photocatalytic performance than pure TiO2 NTs. The corresponding hydrogen evolution rate of Ag/TiO2 NTs prepared with 0.002 M AgNO3 solution was 3.3 times as that of pure TiO2 NTs in the test condition. Additionally, the mechanism of catalyst activity enhanced by SPR effect was proposed. 相似文献
3.
Background Purpose
Photocatalytic water splitting for hydrogen evolution is a potential way to solve many energy and environmental issues. Developing visible-light-active photocatalysts to efficiently utilize sunlight and finding proper ways to improve photocatalytic activity for H2 evolution have always been hot topics for research. This study attempts to expand the use of sunlight and to enhance the photocatalytic activity of TiO2 by N doping and Au loading.Methods
Au/N-doped TiO2 photocatalysts were synthesized and successfully used for photocatalytic water splitting for H2 evolution under irradiation of UV and UV–vis light, respectively. The samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), and photoelectrochemical characterizations.Results
DRS displayed an extension of light absorption into the visible region by doping of N and depositing with Au, respectively. PL analysis indicated electron-hole recombination due to N doping and an efficient inhibition of electron-hole recombination due to the loaded Au particles. Under the irradiation of UV light, the photocatalytic hydrogen production rate of the as-synthesized samples followed the order Au/TiO2 > Au/N-doped TiO2 > TiO2 > N-doped TiO2. While under irradiation of UV–vis light, the N-TiO2 and Au/N-TiO2 samples show higher H2 evolution than their corresponding nitrogen-free samples (TiO2 and Au/TiO2). This inconsistent result could be attributed to the doping of N and the surface plasmonic resonance (SPR) effect of Au particles extending the visible light absorption. The photoelectrochemical characterizations further indicated the enhancement of the visible light response of Au/N-doped TiO2.Conclusion
Comparative studies have shown that a combination of nitrogen doping and Au loading enhanced the visible light response of TiO2 and increased the utilization of solar energy, greatly boosting the photocatalytic activity for hydrogen production under UV–vis light. 相似文献4.
Adawiya J. Haider Amin Daway Thamir Aus A. Najim Ghalib A. Ali 《Plasmonics (Norwell, Mass.)》2017,12(1):105-115
Titanium dioxide (TiO2) has been extensively studied and demonstrated to be suitable to enhance the efficiency of solar cell. In this work, TiO2 is doped with silver nanoparticles (AgNP’s) on glass and the Si substrate by using Pulsed Laser Deposition (PLD) technique. UV–vis spectroscopy, X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Atomic Force Microscope (AFM), electrical conductivity (σ dc), Hall coefficient (RH), current–voltage (I–V), and capacity–voltage (C–V) characterizations have been used to examine the optical, the morphological, and the electrical properties of the films. It has been found that 5 wt.% (Ag) doped TiO2 thin film has the most effect on efficiency of TiO2:Ag /Si solar cell. The (I–V) characteristics showed that the (TiO2) thin film enhances the efficiency of the (p–n) junction solar cell from 1.26 % pure TiO2 to 7.19 % with doping of noble metal (Ag) representing improvement in the efficiency of solar cell leading to estimate empirical equations between efficiency, extinction coefficient, and energy band gap which have a total fit with the experimental data. 相似文献
5.
L. Fisher S. Ostovapour P. Kelly K.A. Whitehead K. Cooke E. Storgårds 《Biofouling》2014,30(8):911-919
Titanium dioxide (TiO2) surfaces doped with molybdenum (Mo) were investigated to determine if their photocatalytic ability could enhance process hygiene in the brewery industry. Doping TiO2 with Mo showed a 5-log reduction in bacterial counts within 4 to 24?h and a 1-log reduction in yeast numbers within 72?h. The presence of a dilute brewery soil on the surface did not interfere with antimicrobial activity. The TiO2–Mo surface was also active in the dark, showing a 5-log reduction in bacteria within 4 to 24?h and a 1-log reduction in yeast numbers within 72?h, suggesting it could have a novel dual function, being antimicrobial and photocatalytic. The study suggests the TiO2–Mo coating could act as a secondary barrier in helping prevent the build-up of microbial contamination on surfaces within the brewery industry, in particular in between cleaning/disinfection regimes during long production runs. 相似文献
6.
Byung-Hoon Kim Doman Kim Dong-Lyun Cho Sung-Hoon Lim So young Yoo Joong-ki Kook Yong ick Cho Seung-Ho Ohk Yeong-Mu Ko 《Biotechnology and Bioprocess Engineering》2007,12(2):136-139
Streptococcus mutans is one of the more significant pathogens involved in the development of dental caries in humans. The purpose of this research
was to design a TiO2-coated dental instrument and to determine the bactericidal effects of the instrument onS. mutants. TiO2 photocatalytic films were prepared by the low-pressure metal-organic chemical vapor deposition (LPMOCVD) method using titanium
tetraisopropoxide (TTIP) as precursor. The photocatalytic reaction was carried out on a TiO2-coated pyrex petri dish with an ultraviolet (UV) light emitting diode (LED) illuminator or a fluorescent lamp light source.
Our data indicates that the relative survival ratio ofS. mutans when plated onto TiO2 photocatalytic films and under exposure to UV-A light for 15 min was 0.01%. In addition, a fluorescent lamp light source
also had bactericidal effects on theS. mutans plated TiO2 photocatalytic films. These results indicate that TiO2-coated dental materials or devices may be useful in dental treatments for the prevention of carious or enamel demineralization. 相似文献
7.
Daiane de Lima Alves Menezes Katia Cristina Zanatta Enderson Sérgio Bannwart Eduardo Antonelli Maurício Rodriguez Chialanza Germán Azcune José Ezequiel De Souza Seila Rojas de Souza 《Luminescence》2024,39(4):e4732
In the present work, glass samples in the (100 − x)B2O3–xLi2O binary system, with x varying from 30 to 50 mol%, were prepared using the conventional melting and moulding method, with the main objective of evaluating the thermoluminescence response when exposing these materials to ultraviolet (UV) radiation. Complementary analysis based on density, optical absorption on the UV–visible region (UV–vis absorbance), Fourier transform infrared spectroscopy on the medium region, X-ray diffraction, and differential thermal analysis measurements were performed. Thermoluminescence measurements of vitreous samples showed glow curves with at least one peak with a maximum temperature of ~170°C after exposure to UV radiation in the temperature range 50–250°C. Samples were also exposed to beta radiation in the temperature range 25–275°C, also showing single peaks with a maximum temperature of ~150°C. 相似文献
8.
A. Wouter Maijenburg Eddy J.B. Rodijk Michiel G. Maas Johan E. ten Elshof 《Journal of visualized experiments : JoVE》2014,(87)
Photocatalytically active nanostructures require a large specific surface area with the presence of many catalytically active sites for the oxidation and reduction half reactions, and fast electron (hole) diffusion and charge separation. Nanowires present suitable architectures to meet these requirements. Axially segmented Ag|ZnO and radially segmented (coaxial) TiO2-Ag nanowires with a diameter of 200 nm and a length of 6-20 µm were made by templated electrodeposition within the pores of polycarbonate track-etched (PCTE) or anodized aluminum oxide (AAO) membranes, respectively. In the photocatalytic experiments, the ZnO and TiO2 phases acted as photoanodes, and Ag as cathode. No external circuit is needed to connect both electrodes, which is a key advantage over conventional photo-electrochemical cells. For making segmented Ag|ZnO nanowires, the Ag salt electrolyte was replaced after formation of the Ag segment to form a ZnO segment attached to the Ag segment. For making coaxial TiO2-Ag nanowires, a TiO2 gel was first formed by the electrochemically induced sol-gel method. Drying and thermal annealing of the as-formed TiO2 gel resulted in the formation of crystalline TiO2 nanotubes. A subsequent Ag electrodeposition step inside the TiO2 nanotubes resulted in formation of coaxial TiO2-Ag nanowires. Due to the combination of an n-type semiconductor (ZnO or TiO2) and a metal (Ag) within the same nanowire, a Schottky barrier was created at the interface between the phases. To demonstrate the photocatalytic activity of these nanowires, the Ag|ZnO nanowires were used in a photocatalytic experiment in which H2 gas was detected upon UV illumination of the nanowires dispersed in a methanol/water mixture. After 17 min of illumination, approximately 0.2 vol% H2 gas was detected from a suspension of ~0.1 g of Ag|ZnO nanowires in a 50 ml 80 vol% aqueous methanol solution. 相似文献
9.
Yao-Hsuan Tseng Der-Shan Sun Wen-Shiang Wu Hao Chan Ming-Syuan Syue Han-Chen Ho Hsin-Hou Chang 《Biochimica et Biophysica Acta (BBA)/General Subjects》2013
Background
Traditional antibacterial photocatalysts are primarily induced by ultraviolet light to elicit antibacterial reactive oxygen species. New generation visible-light responsive photocatalysts were discovered, offering greater opportunity to use photocatalysts as disinfectants in our living environment. Recently, we found that visible-light responsive platinum-containing titania (TiO2–Pt) exerted high performance antibacterial property against soil-borne pathogens even in soil highly contaminated water. However, its physical and photocatalytic properties, and the application in vivo have not been well-characterized.Methods
Transmission electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, ultraviolet–visible absorption spectrum and the removal rate of nitrogen oxides were therefore analyzed. The antibacterial performance under in vitro and in vivo conditions was evaluated.Results
The apparent quantum efficiency for visible light illuminated TiO2–Pt is relatively higher than several other titania photocatalysts. The killing effect achieved approximately 2 log reductions of pathogenic bacteria in vitro. Illumination of injected TiO2–Pt successfully ameliorated the subcutaneous infection in mice.Conclusions
This is the first demonstration of in vivo antibacterial use of TiO2–Pt nanoparticles. When compared to nanoparticles of some other visible-light responsive photocatalysts, TiO2–Pt nanoparticles induced less adverse effects such as exacerbated platelet clearance and hepatic cytotoxicity in vivo.General significance
These findings suggest that the TiO2–Pt may have potential application on the development of an antibacterial material in both in vitro and in vivo settings. 相似文献10.
Nura Abdullahi Elias Saion Abdul Halim Shaari Naif Mohammed Al-Hada Aysar Keiteb 《PloS one》2015,10(5)
MWCNTs/TiO2 nanocomposite was prepared by oxidising MWCNT in H2SO4/HNO3 then decorating it with TiO2-p25 nanopowder. The composites were characterised using XRD, TEM, FT-IR PL and UV−vis spectroscopy. The TEM images have shown TiO2 nanoparticles immobilised onto the sidewalls of the MWCNTs. The UV-vis spectrum confirms that the nanocomposites can significantly absorb more light in the visible regions compared with the commercial TiO2 (P25). The catalytic activity of these nanocomposites was determined by photooxidation of MB aqueous solution in the presence of visible light. The MWCNTs/TiO2 (1:3) mass ratio showed maximum degradation efficiency. However, its activity was more favourable in alkaline and a neutral pH than an acidic medium. 相似文献
11.
Ye Li Zhenping Qin Hongxia Guo Hanxiao Yang Guojun Zhang Shulan Ji Tingying Zeng 《PloS one》2014,9(12)
In this work, the positively or negatively charged anatase TiO2 nanoparticles were synthesized via a low temperature precipitation-peptization process (LTPPP) in the presence of poly(ethyleneimine) (PEI) and poly(sodium4- styrenesulfonate) (PSS). X-ray diffraction (XRD) pattern and high-resolution transmission electron microscope (HRTEM) confirmed the anatase crystalline phase. The charges of the prepared TiO2, PEI-TiO2 and PSS-TiO2 nanoparticles were investigated by zeta potentials. The results showed that the zeta potentials of PEI-TiO2 nanoparticles can be tuned from +39.47 mV to +95.46 mV, and that of PSS-TiO2 nanoparticles can be adjusted from −56.63 mV to −119.32 mV. In comparison with TiO2, PSS-TiO2 exhibited dramatic adsorption and degradation of dye molecules, while the PEI modified TiO2 nanoparticles showed lower photocatalytic activity. The photocatalytic performances of these charged nanoparticles were elucidated by the results of UV-vis diffuse reflectance spectra (DRS) and the photoluminescence (PL) spectra, which indicated that the PSS-TiO2 nanoparticles showed a lower recombination rate of electron-hole pairs than TiO2 and PEI-TiO2. 相似文献
12.
Anatase TiO2 is an extensively studied anode material for lithium‐ion batteries because of its superior capability of storing Li+ electrochemically. Here reversible lithium storage of TiO2 is achieved chemically using redox targeting reactions. In the presence of a pair of redox mediators, bis(pentamethylcyclopentadienyl)cobalt (CoCp* 2) and cobaltocene (CoCp2) in an electrolyte, TiO2 and its lithiated form Li x TiO2 can be reduced and oxidized by CoCp* 2 and CoCp2 +, respectively, which accompany Li+ insertion and extraction, albeit without attaching the TiO2 onto the electrode. The reversible chemical lithiation/delithiation and the involved phase transitions are unambiguously confirmed using density functional theory (DFT) calculations, UV‐vis spectroscopy, X‐ray photoelectron spectoscopy (XPS), and Raman spectroscopy. A redox flow lithium‐ion battery (RFLB) half‐cell is assembled and evaluated, which is a critical step towards the development of RFLB full cells. 相似文献
13.
Hailong Xiong Lanlan Wu Yu Liu Tunan Gao Kaiqian Li Yan Long Rui Zhang Ling Zhang Zhen‐An Qiao Qisheng Huo Xin Ge Shuyan Song Hongjie Zhang 《Liver Transplantation》2019,9(31)
Multiphasic titanium dioxide (TiO2) possessing abundant heterophase junctions have been widely used for various photocatalytic applications. Current synthesis of multiphasic TiO2 mainly involves the process of thermal treatment and multiple steps of rigorous reactions, which is adverse to controlling the crystal phases and phase ratios of multiphasic TiO2. Meanwhile, the resulting products have relatively low surface area and nonporous structure. Here, a facile polymer‐assisted coordination‐mediated self‐assembly method to synthesize mesoporous TiO2 polymorphs with controllable heterophase junctions and large surface area by using polyethylenimine as the porogen in an acidic aqueous synthesis system is reported. Using this approach, the crystal phases (triphase, biphase, and monophase) and phase compositions (0–100%) are easily tailored by selecting the suitable acidic media. Furthermore, the specific surface areas (77–228 m2 g?1) and pore sizes (2.9–10.1 nm) are readily tailored by changing the reaction temperature. The photocatalytic activity of mesoporous TiO2 polymorphs is evaluated by photocatalytic hydrogen evolution. The triphasic TiO2 exhibits an excellent photocatalytic H2 generation rate of 3.57 mmol h?1 g?1 as compared to other polymorphs, which is attributed to the synergistic effects of heterophase junctions and mesostructure. The band diagram of possible electron transfer pathway for triphasic TiO2 is also elucidated. 相似文献
14.
Li Li Shan Xiaoxue Zhang Yuchong Wang Jin Liao Zilong Gu Yuxi Chen Shuai Jiang Youjun Chen Jinying 《Luminescence》2022,37(2):190-198
A semiconductor nano-material was prepared, and its degradation efficiency of zearalenone (ZEN) was studied. The photocatalytic material graphitic carbon nitride (g-C3N4) was synthesized by the traditional method of hot cracking. Its structure was characterized by X-ray diffraction (XRD), Fourier-transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The photocatalytic degradation experiment showed that under the irradiation of ultraviolet (UV) lamp (254 nm, including 185 nm), g-C3N4 could induce photocatalytic effect, which provided a new method for the degradation of ZEN in real powder samples. The experimental conditions of photocatalytic degradation of the primary reference material of ZEN and ZEN in real powder samples were explored. And the degradation products of ZEN were analyzed after high-performance liquid chromatography–mass spectrometry (HPLC–MS). Under each optimal experimental conditions, the degradation rate on primary reference material of ZEN and ZEN in real powder samples was 96.0% and 50.0%, respectively. The results in this work provide a theoretical reference and practical basis for the photocatalytic degradation of mycotoxin in real powder samples by g-C3N4. 相似文献
15.
In this paper, bis(2 methyl-8-hydroxyquinoline) zinc (Zn(mq)2) nanoparticles were synthesised at room temperature by a simple chemical precipitation method. The Zn(mq)2 nanoparticles were characterised by powder X-ray diffraction (PXRD) analysis to confirm the crystalline nature of the Zn(mq)2 nanoparticles. The morphology and the elemental composition of Zn (mq)2 nanoparticles were analysed by high-resolution scanning electron microscopy (HR-SEM) and energy dispersive X-ray analysis (EDAX). The functional groups of the compound were studied with the help of Fourier transform infrared spectroscopy (FTIR) and FT Raman spectroscopy. Further, Zn (mq)2 nanoparticles were characterised by C-13 NMR spectroscopy, mass spectroscopy and CHN analysis. The thermal stability of the particles was studied using TG-DSC curve. The optical properties of the particles were studied by means of UV–Visible spectroscopy. The luminescence property of the synthesised particles was observed from the photoluminescence spectrum to confirm the possible application in organic light emitting diode. 相似文献
16.
Cu (II) and Ag(I) together with TiO2 powder were deposited on conducting support substrates to enhance the photocatalytic ability. The catalytic efficiency was
tested by monitoring the photocatalytic degradation and detriment of methylene blue (MB) and bovine serum albumin (BSA). The
conformational change of BSA induced by catalysts was also observed by circular dichroism spectroscopy.The antibacterial activities
were studied by Escherichia coli. Both MB and BSA could be degraded more efficiently than pure TiO2. After treatment with catalyst, the morphology of cells became twisted and rougher. Regular wrinkles were damaged and groove-like
rift appeared on the surface. The fluorescence polarization has shown a significant decrease in membrane fluidity and the
increase of permeability of cell membrane. Changes of the spectral profile of E. coli were observed, which suggested the damages of surface groups on the cell membrane. 相似文献
17.
Immobilized TiO2 photocatalysts were used to sterilize and reclaim the wastewater of bean sprout cultivation from a continuous hydro-circulation system. The photocatalysts effectively killed bacteria and degraded organic pollutants in the wastewater. Stimulation of bean sprout growth and suppression of decaying pathogens were also induced by the TiO2 photocatalytic activity. 相似文献
18.
Jung Kon Kim Hack Sun Choi Eungbin Kim Young Sang Lee Yong Ho Kim Si Wouk Kim 《Biotechnology letters》2002,24(17):1397-1400
A novel and highly effective UV-TiO2 photocatalytic reactor was developed for killing microorganisms, including Escherichia coli. Among tested four types of TiO2-immobilized photocatalytic supporters (glass bead, muscovite bead, alginate bead, and TiO2 thin film coated quartz tube), the muscovite bead had a 99.9% percent bactericidal activity within 5 min along with permanent longevity. Adding air bubbles or H2O2 (<50 mg l–1) to the sample solution significantly enhanced the killing activity in that 100% percent of bacterial cells were killed within 3 min. 相似文献
19.
The present investigation reports, the synthesis of manganese oxide (α-Mn2O3) nanobundles using thermal decomposition and its physicochemical characterization. The α-Mn2O3 nanobundles have been prepared using manganese oxalate dihydrate powders as precursor in the presence of oleylamine and triphenylphosphine as solvent and capping agent. Transmission electron microscopy (TEM) analysis demonstrated Mn2O3 nanobundles compose of nanospheres with diameter 30 nm. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectroscopy. Manganese oxide nanocrystals have been prepared under different condition. The controlled experimental results showed that the use of oleylamine and triphenylphosphine as the solvent and capping agent in the chemical process played important role in the formation of the final products. 相似文献
20.
Photochemical treatment is increasingly being applied to remedy environmental problems. TiO2-derived catalysts are efficiently and widely used in photodegradation applications. The efficiency of various photochemical treatments, namely, the use of UV irradiation without catalyst or with TiO2/graphene-TiO2 photodegradation methods was determined by comparing the photodegadation of two main types of hydrophobic chlorinated aromatic pollutants, namely, pentachlorophenol (PCP) and polychlorinated biphenyls (PCBs). Results show that photodegradation in methanol solution under pure UV irradiation was more efficient than that with either one of the catalysts tested, contrary to previous results in which photodegradation rates were enhanced using TiO2-derived catalysts. The effects of various factors, such as UV light illumination, addition of methanol to the solution, catalyst dosage, and the pH of the reaction mixture, were examined. The degradation pathway was deduced. The photochemical treatment in methanol soil washing solution did not benefit from the use of the catalysts tested. Pure UV irradiation was sufficient for the dechlorination and degradation of the PCP and PCBs. 相似文献