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Localized Surface Plasmon Resonance Enhanced Photocatalytic Hydrogen Evolution via Pt@Au NRs/C <sub/>3</sub> N <sub/>4</sub> Nanotubes under Visible-Light Irradiation
摘要： Au nanorods (NRs) decorated carbon nitride nanotubes (Au NRs/CNNTs) photocatalysts have been designed and prepared by impregnation–annealing approach. Localized surface plasmon resonance (LSPR) peaks of Au NRs can be adjusted by changing the aspect ratios, and the light absorption range of Au NRs/CNNTs is extended to longer wavelength even near-infrared light. Optimal composition of Pt@Au NR769/CNNT650 has been achieved by adjusting the LSPR peaks of Au NRs and further depositing Pt nanoparticles (NPs), and the photocatalytic H2 evolution rate is 207.0 μmol h?1 (20 mg catalyst). Preliminary LSPR enhancement photocatalytic mechanism is suggested. On one hand, LSPR of Au NRs is beneficial for visible-light utilization. On the other hand, Pt NPs and Au NRs have a synergetic enhancement effect on photocatalytic H2 evolution of CNNTs, in which the local electromagnetic field can improve the photogenerated carrier separation and direct electron transfer increases the hot electron concentration while Au NRs as the electron channel can well restrain charge recombination, finally Pt as co-catalyst can boost H+ reduction rate. This work provides a new way to develop efficient photocatalysts for splitting water, which can simultaneously extend light absorption range and facilitate carrier generation, transportation and reduce carrier recombination.
关键词： synergetic effect,plasmonic photocatalysts,carbon nitride nanotubes,Au nanorods,photocatalytic H2 evolution
更新于2025-09-09 09:28:46
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Improved Electrical Stability of Silver NWs Based Hybrid Transparent Electrode interconnected with Polymer Functionalized CNTs
摘要： Silver nanowires have high potential to replace the conventional transparent conductors in many applications. However, the electrical instability of silver nanowires especially when heated as a result of electrical current passage cause the failure of this type of conductors and thus may limit their uses in many applications. In this study, a novel approach based on interconnecting the individual nanowires with conductive polymer wrapped carbon nanotubes is examined to improve the stability of silver nanowires network. The hybrid electrode with modified carbon nanotubes shows highly stable electrical performance in comparison to silver nanowires electrode. Under continuous electrical stress, slight variation in the sheet resistance of the hybrid electrode was noticed and was about two order of magnitude less than that of silver nanowires electrode. Moreover, the thermal studies reveal that the hybrid electrode stabilizes at much lower temperature than that of silver nanowires electrodes. The findings show that the proposed approach is very promising to overcome the failure issue of silver nanowires and to increase the feasibility of their use for device applications.
关键词： Silver nanowires,optical properties,electrical stability,transparent conductor,Carbon nanotubes
更新于2025-09-09 09:28:46
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Photochemical deposition of silver on Fe2O3 nanotubes prepared by anodization and exploring their photoelectrochemical activity
摘要： Novel silver-decorated Fe2O3 nanotubes (Ag/FeNT) have been synthesized by a simple, fast and efficient method. Fe2O3 nanotubes (FeNT) have been successfully synthesized on pure iron plates by electrochemical anodizing, followed by silver deposition on the surface of the nanotubes through photodeposition. Various instrumental techniques have been used to investigate the morphology, structure and optical properties of the prepared samples. In addition, the photoelectrochemical water splitting performance of the new electrodes has been studied. An increased photocurrent density and a greatly enhanced onset potential for photoelectrochemical activity have been shown by Ag/FeNT electrodes in comparison with bare FeNT. Silver-decorated Fe2O3 nanotube (sample Ag/FeNT1) shows an almost 2.5-fold increase in photocurrent compared with bare Fe2O3 nanotube. Efficient charge carrier separation, visible light sensitization due to Ag nanoparticles on Fe2O3 nanotube and enhanced electrical conductivity are responsible for the increase in the photoelectrochemical water splitting activity of Ag/FeNT.
关键词： Water splitting,Silver deposition,Fe2O3 nanotubes,Photoelectrochemical activity
更新于2025-09-09 09:28:46
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Charge separation and ROS generation on tubular sodium titanates exposed to simulated solar light
摘要： The research focuses on a few key points concerning the light-driven processes taking place on TiO2 anatase and sodium titanates with tubular morphology, such as the relationship between the morphology and activity for H2 and CO2 production, density of surface hydroxyl groups, ROS (?OH and ?O2-) production and photocatalytic activity, and charge separation at the interface of semiconducting domains and enhancement of activity. One key point discussed is whether the materials with peculiar morphologies (i.e. tubular) are superior to the conventional ones. The experimental evidences show that the main advantage of the tubular morphology of sodium titanate is given by its significantly higher surface area compared to parental anatase. FTIR and XPS progressive analyses evidence that the density of surface hydroxyl groups decreases with the development of the tubular morphology. The radical trapping experiments show that the variation of surface hydroxyl density is, generally, followed by activities for ?OH and ?O2- generation, as well as by the photocatalytic production of H2 and CO2 from water/methanol mixture. Consequently, the ROS, formed by action of photogenerated electrons and holes on adsorbed O2 and hydroxyl groups, respectively, play an important role in determining the photocatalytic activity of titania-based materials. The other major aspect revealed by this research is that the charge separation at the interfaces formed between anatase and sodium titanate crystalline phases has remarkable effect on the activity formation rates of H2 and CO2.
关键词： titanate nanotubes,reactive oxygen species,charge separation,simulated solar light,photocatalysis
更新于2025-09-09 09:28:46
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Chemometric Approaches for Developing Infrared Nanosensors to Image Anthracyclines
摘要： Generation, identification, and validation of optical probes to image molecular targets in a biological milieu remains a challenge. Synthetic molecular recognition approaches leveraging the intrinsic near-infrared fluorescence of single-walled carbon nanotubes is a promising approach for long-term biochemical imaging in tissues. However, generation of nanosensors for selective imaging of molecular targets requires a heuristic approach. Here, we present a chemometric platform for rapidly screening libraries of candidate single-walled carbon nanotube nanosensors against biochemical analytes to quantify fluorescence response to small molecules including vitamins, neurotransmitters, and chemotherapeutics. We further show this approach can be leveraged to identify biochemical analytes that selectively modulate the intrinsic near-infrared fluorescence of candidate nanosensors. Chemometric analysis thus enables identification of nanosensor-analyte ‘hits’ and also nanosensor fluorescence signaling modalities such as wavelength-shifts that are optimal for translation to biological imaging. Through this approach, we identify and characterize a nanosensor for the chemotherapeutic anthracycline doxorubicin, which provides an up to 17 nm fluorescence red-shift and exhibits an 8 μM limit of detection, compatible with peak circulatory concentrations of doxorubicin common in therapeutic administration. We demonstrate selectivity of this nanosensor over dacarbazine, a chemotherapeutic commonly co-injected with DOX. Lastly, we demonstrate nanosensor tissue compatibility for imaging of doxorubicin in muscle tissue by incorporating nanosensors into the mouse hindlimb and measuring nanosensor response to exogenous DOX administration. Our results motivate chemometric approaches to nanosensor discovery for chronic imaging of drug partitioning into tissues and towards real-time monitoring of drug accumulation.
关键词： fluorescence response,single-walled carbon nanotubes,infrared nanosensors,biological imaging,doxorubicin,chemometric approaches,anthracyclines
更新于2025-09-09 09:28:46
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Bright and Ultrafast Photoelectron Emission from Aligned Single-Wall Carbon Nanotubes through Multiphoton Exciton Resonance
摘要： Ultrashort bunches of electrons, emitted from solid surfaces through excitation by ultrashort laser pulses, are an essential ingredient in advanced X-ray sources and ultrafast electron diffraction spectroscopy. Multiphoton photoemission using a noble metal as the photocathode material is typically used, but more brightness is desired. Artificially structured metal photocathodes have been shown to enhance optical absorption via surface plasmon resonance, but such an approach severely reduces the damage threshold in addition to requiring state-of-the-art facilities for photocathode fabrication. Here, we report ultrafast photoelectron emission from sidewalls of aligned single-wall carbon nanotubes. We utilized strong exciton resonances, inherent in this prototypical one-dimensional material, as well as the high damage threshold owing to their excellent thermal conductivity and mechanical rigidity. We obtained unambiguous evidence for resonance-enhanced multiphoton photoemission processes with definite power-law behaviors. In addition, we observed strong polarization dependence and ultrashort photoelectron response time, both of which can be quantitatively explained by our model. These results firmly establish aligned single-wall carbon nanotube films as a novel and promising ultrafast photocathode material.
关键词： depolarization effect,ultrafast,multiphoton,photoemission,carbon nanotubes,photocathode
更新于2025-09-09 09:28:46
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Degradation of tartrazine and hydrogen production simultaneously with combination of photocatalysis-electrocoagulation
摘要： Degradation of tartrazine dye and the production of hydrogen simultaneously with a combination of photocatalysis and electrocoagulation has been investigated. The photocatalytic process was performed by using a catalyst of TiO2 nanotubes that had been synthesized by anodizing method. In electrocoagulation process used Al-SS 316 electrode with variation of voltage: 5V, 10V, and 15V. The structure of TiO2 catalyst with nanotubes morphology was characterized by SEM-Mapping, FTIR, XRD, and UV-Vis DRS. The optimum condition obtained from the electrocoagulation process is at a voltage of 15V with a test time of 4 hours. From the results of photocatalysis with TiO2 nanotubes obtained percent degradation of tartrazine dye equal to 48.86% and simultaneously produced 0.87 ml of H2 with concentration 3.46%. The use of aluminum plate as anode and 316 stainless steel plate as cathode in electrocoagulation process has also succeeded degrading tartrazine dye by 82.45% and produced 3.88 ml of H2 with concentration 12.14%. The result of the combination of photocatalysis and electrocoagulation process obtained degradation conversion of tartrazine dye by 90.68% with final dye concentration to 1.93 ppm and simultaneously H2 products as much as 5.97 ml with a concentration of 12.41% can be produced. The final concentration of tartrazine dye waste from combination of photocatalysis-electrocoagulation process is safe to be disposed into the environment because it meets the quality standard. In addition, the production of H2 has potential as a renewable energy source.
关键词： electrocoagulation,tartrazine,hydrogen production,TiO2 nanotubes,photocatalysis
更新于2025-09-09 09:28:46
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Dynamically Configurable Nonlinear Optical Switching Based on Vertically Aligned Carbon Nanotubes
摘要： The modification of the third order nonlinear optical response exhibited by vertically aligned carbon nanotubes in two-wave mixing interactions was analyzed. All-optical switching effects were explored by using a vectorial optical Kerr gate with nanosecond pulses at 532 nm wavelength of excitation. The samples were prepared by a spray pyrolysis method. Morphological and structural characterization of the samples was conducted by Scanning Electron Microscopy, Transmission Electron Microscopy and Raman Spectroscopy studies. Important structural changes dependent on the temperature employed for the preparation of the carbon nanotubes were observed. It was highlighted a remarkable influence of nonlinear energy transference in spatially-resolved optical processes for designing ultrafast low-dimensional devices.
关键词： aligned carbon nanotubes,Nonlinear Optics,Two-wave mixing
更新于2025-09-09 09:28:46
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Photoelectrochemical activity of Ag loaded TiO2 nanotube arrays produced by sequential chemical bath deposition for water splitting
摘要： We report on remarkable improvement of photoelectrochemical (PEC) properties of TiO2 nanotubes by loading of Ag nanoparticles into them. The silver nanoparticles were loaded on the nanotubes by sequential chemical bath deposition (S-CBD) with different number of deposition cycles. Various characterizations including field emission scanning electron microscopy, X-ray diffraction, and energy dispersive X-ray analysis (EDX), all confirm that the silver nanoparticles were deposited inside and outside of TiO2 nanotubes. In addition, the PEC properties of the samples were investigated using linear sweep voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. The PEC analyses clearly show that the photoelectrochemical activity of the Ag-loaded samples are considerably higher than the bare TiO2 nanotubes (about 3 times). This mostly originates from the improvement of light absorption due to the plasmonic effects in addition to better separation and transport of electron–hole pairs in the Ag-loaded samples relative to the bare TiO2 nanotubes. All results indicate that the maximum efficiency were obtained for the 8-cycle of S-CBD Ag-loading on the bare TiO2 nanotubes.
关键词： TiO2 nanotubes,sequential chemical bath deposition,water splitting,photoelectrochemical,Ag nanoparticles
更新于2025-09-09 09:28:46
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Optimization of the liquid–liquid interfacial precipitation method for the synthesis of $$\hbox {C}_{60}$$C60 nanotubes
摘要： Tubular fullerene nanowhiskers called ‘fullerene nanotubes’ are composed of C60 fullerene molecules (C60 NTs) are synthesized at room temperature using the liquid–liquid interfacial precipitation method in the pyridine and isopropyl alcohol (IPA) system. The growth control of fullerene nanotubes is important for their chemical and physical properties as well as for their future applications. In the present study, we investigated the effect of light, water, solvent ratio and temperature on the synthesis of C60 nanotubes. A marked development in the yield of C60 NTs was achieved using dehydrated solvents, a solution with a volume ratio of 1:9 for pyridine: IPA, a growth temperature equal to 5?C and by illuminating the C60-pyridine solution with ultraviolet light (wavelength 302 nm) for 102 h. The synthesized fullerene nanotubes were characterized by different analytical techniques including Raman and Fourier transform infrared spectroscopy, optical microscopy, focussed ion beam scanning electron microscopy and transmission electron microscopy.
关键词： solution growth,liquid–liquid interfacial precipitation method,light,temperature,solvent,Fullerene nanotubes
更新于2025-09-09 09:28:46