- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
One-Step Controlled Synthesis of Size-Tunable Toroidal Gold Particles for Biochemical Sensing
摘要： Controlling the size and shape of nanoparticles is a major goal in materials science. Here we show the fast, 30-minute, controlled one-step synthesis of gold particles (tAUPs) with sizes tunable from 350 nm to 1.7 microns by using a mixture of surfactant scaffolds made from sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB). The as-synthesized tAUPs have nanospikes that protrude either inwards or outwards from the ring cavity. The number of nanospikes can be tuned by a two-step temperature change process to create so-called rough tAUPs. The toroidal gold particle structures exhibit surface plasmon extinction peaks in the near infrared-region and demonstrate a high surface-enhanced Raman scattering (SERS) sensitivity for the detection of 4-mercaptobenzoic acid (4-MBA) molecules. The protruding nanospikes significantly enhance the electromagnetic field oscillating inside the ring cavity. This is confirmed through sensitive detection of 4-MBA molecules as well as by simulation. Rough tAUP structures generate the highest sensitivity with an estimated total enhancement (TE) factor of 3.33 ×106, which is two orders of magnitude greater than reported by gold nanostars. A variety of different gold structures such as gold nanodendrites, nanowires, and nanochains can be obtained by changing the SDS to CTAB concentration ratios. The unique structures and plasmonic properties of tAUPs hold promise for ultrasensitive biochemical sensing.
关键词： toroidal gold particles (tAUPs),binary capping,surface-enhanced Raman scattering,mild reduction,surfactant template
更新于2025-09-11 14:15:04
-
Enhanced sunlight photocatalytic degradation of methylene blue by rod-like ZnO-SiO2 nanocomposite
摘要： This work aims to develop a novel and economical rod-like zinc oxide–silicon dioxide (ZS) nanocomposite by a simple co-precipitation method with different surfactants, such as cationic surfactant cetyl triethylammonium bromide (CTAB), non-ionic polymer polyvinyl pyrrolidone (PVP), and an anionic surfactant sodium dodecyl sulfate (SDS). The phase identification, surface topography and optical properties were analyzed by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), UV-Visible and Photoluminescence Spectroscopy. The photocatalytic degradation efficiency of the prepared nanocomposite was measured using model organic pollutant of methylene blue (MB) in water under sun light irradiation. Due to surface plasmon resonance (SPR) effect of SiO2 nanoparticles, ZS nanocomposite shows an absorption peak (434 nm) in the visible region. Hence the maximal MB degradation efficiency of 97.8% was achieved under 90 min of sunlight irradiation. Among the three surface-active agents, cationic surfactant shows the highest degradation ability with ZS nanocomposite. This work will open a new platform for further development of ZS-based nanocomposites to solve the global photocatalytic and waste water treatment problem.
关键词： ZnO–SiO2,Co-precipitation,Sun light,Surfactant,Methylene blue
更新于2025-09-11 14:15:04
-
Synthesis of Mesoporous TiO2/Boron-Doped Diamond Photocatalyst and Its Photocatalytic Activity under Deep UV Light (λ = 222 nm) Irradiation
摘要： There is a need for highly efficient photocatalysts, particularly for water purification. In this study, we fabricated a mesoporous TiO2 thin film on a boron-doped diamond (BDD) layer by a surfactant-assisted sol-gel method, in which self-assembled amphiphilic surfactant micelles were used as an organic template. Scanning electron microscopy revealed uniform mesopores, approximately 20 nm in diameter, that were hexagonally packed in the TiO2 thin film. Wide-angle X-ray diffraction and Raman spectroscopy clarified that the framework crystallized in the anatase phase. Current–voltage (I–V) measurements showed rectification features at the TiO2/BDD heterojunction, confirming that a p–n hetero-interface formed. The as-synthesized mesoporous TiO2/BDD worked well as a photocatalyst, even with a small volume of TiO2 (15 mm × 15 mm × c.a. 1.5 μm in thickness). The use of deep UV light (λ = 222 nm) as a light source was necessary to enhance photocatalytic activity, due to photo-excitation occurring in both BDD and TiO2.
关键词： photocatalyst,water purification,thin film,surfactant-assisted sol-gel method,p-n heterojunction,deep UV light,mesoporous metal oxide
更新于2025-09-10 09:29:36
-
AIP Conference Proceedings [Author(s) 6TH INTERNATIONAL CONFERENCE ON PRODUCTION, ENERGY AND RELIABILITY 2018: World Engineering Science & Technology Congress (ESTCON) - Kuala Lumpur, Malaysia (13–14 August 2018)] - Development of nanocomposites on the basis of graphene nanoplatelets
摘要： The prospects for using a phenol-formaldehyde resin (PFR) as a reactive surfactant in the preparation of highly concentrated dispersions of carbon nanostructured materials (up to 1 %) are considered in the present paper. Modifying graphene nanoplatelets (GNPs) with this surfactant promotes the effect of targeted self-assembly of carbon nanoparticles in solution (with decreasing pH), which makes it possible to obtain nanocomposites with improved properties. It is important that the use of highly concentrated dispersions of PFR-modified GNPs in the production of nanocomposite materials does not require a preliminary removal of the surfactant. Based on the resulting dispersion, the mesoporous carbon/GNPs composite with a developed surface (3000 ? 4000 m2 g?1) was successfully synthesized. It can be used as an electrode material for supercapacitors and an adsorbent of organic and inorganic species for wastewater treatment purposes.
关键词： graphene nanoplatelets,reactive surfactant,self-assembly,nanocomposites,mesoporous carbon,phenol-formaldehyde resin
更新于2025-09-10 09:29:36
-
Surfactant-induced chemical ordering of GaAsN:Bi
摘要： We have examined the in?uence of an incorporating surfactant on chemical ordering in GaAsN:Bi alloys. Epitaxy with a (2 (cid:2) 1) reconstruction leads to the formation of GaAsN alloys, while the introduction of a Bi ?ux induces long-range chemical ordering of the {111} planes of GaAsN:Bi. We propose a mechanism in which Bi enhances the alignment of dimer rows along the [110] direction, facilitating N incorporation beneath surface dimers and Bi incorporation between dimer rows to form alternating N-rich and Bi-rich {111} planes. These ?ndings suggest a route to tailoring the local atomic environment of N and Bi atoms in a wide range of emerging dilute nitride-bismide alloys.
关键词： surfactant,molecular-beam epitaxy,chemical ordering,dilute nitride-bismide alloys,GaAsN:Bi
更新于2025-09-10 09:29:36
-
Wet-chemical preparation of TiO2-nanostructures using different solvents: Effect of CTAB concentration and tentative mechanism of particle formation
摘要： In this paper, TiO2 nanostructures (TiO2-NSs) were synthesized in a controlled way. The effects of the use of a surfactant, Cetyl trimethylammonium bromide (CTAB), and the nature of the solvent of synthesis (ethanol and toluene) on the characteristics of the final product were studied. For this, TiO2-NSs were characterized using IR spectroscopy, X-ray diffraction (XRD), Transmission and Scanning Electron Microscopy. The solid obtained, without heat treatment, presented an amorphous structure that crystallized when treated at 450 °C, giving anatase as crystalline phase, independent of the solvent of synthesis and the concentration of CTAB used. The size of the crystallite in the powders synthesized was 3-5 nm and was reduced on increasing CTAB concentration, regardless of the solvent used. Using ethanol, the primary particles had a spheroidal or needle type shape of nanometric size (<100 nm) and the agglomerates were spherical (1 to 5 μm), reducing in size on the addition of CTAB. On using toluene, irregular-shaped aggregates with acute edges were formed (10 to 20 μm), made up of primary particles nanometric (<100 nm) and with the presence of poros. Given the nature of the synthesis process, a mechanism was proposed to explain the formation of the TiO2-NSs.
关键词： toluene,mechanism of formation,ethanol,TiO2 nanostructures,synthesis,surfactant
更新于2025-09-10 09:29:36
-
Achieving efficient H2O2 production by a visible-light absorbing, highly stable photosensitized TiO2
摘要： In this paper we propose titanium dioxide modified with cobalt(II) 2-ethylhexanoate (Co@TiO2) as photoactive material for the efficient visible light driven production of H2O2. We demonstrate that visible light activity can be achieved thanks to a photoinduced electron transfer from the excited complex towards the TiO2 conduction band that corresponds to a cobalt-to-titanium-charge-transfer transition. H2O2 is synthetized by a combination of oxygen reduction and water oxidation, that is possible thanks to the correct band position of Co@TiO2. A mechanism of H2O2 formation is suggested on the basis of experimental evidences. Reactive oxygen intermediates, together with H2O2 are responsible for the photocatalytic degradation of a nonionic surfactant, of methylene blue and of phenol for wastewater treatments. Finally, and quite interestingly, Co@TiO2 can be also used in a photoelectrochemical setup, where it can be adopted both as photoanode and photocatode, and the switching potential corresponds to the redox potential of the adsorbed complex Co(III)/Co(II) couple.
关键词： photosensitization,charge carrier injection,cobalt(II) 2-ethylhexanoate,surfactant degradation,photocatalysis
更新于2025-09-10 09:29:36
-
A study of spectro photo metric determination of ion association complex, formed by anionic surfactant sodium dodecyl by using crystal violet as a cationic dye in region Bilaspur (Chhattisgarh)
摘要： Surface active agents (SAA) with negative charge of polar group are named as anionic compounds. They are the main constituent of most products containing synthetic surfactants. Anionic surfactants after use are passed into sewage-treatment plants, where they are partially degraded and adsorbed to sewage sludge. Therefore, it is important to investigate the environmental fate of those classes of compounds in more details. A sensitive, selective and inexpensive method for the determination of anionic surfactants in waste water of sewage has been developed. This research involves determination the concentration of anionic surfactants sodium dodecyl sulphate (SDS) with use appropriated analytical techniques in environmental samples. The official methodology for determination of anionic surfactant (AS) in liquid samples is based on the ion-pair reaction of these analysts’ compounds with crystal violet (CV) and an extraction with organic solvent benzene. In an organic solvent benzene anionic surfactant SDS and a cationic dye CV forms an ion association complex. This ion associate exhibits an absorption maximum wave length (λ max) at 560 nm. The method proposed has been found much easier, accurate and rapid, and there is no use of any toxic chemicals.
关键词： crystal violet,Anionic surfactant,Surface active agents,Sodium dodecyl sulphate
更新于2025-09-10 09:29:36
-
Numerical Demonstration of In-Tube Liquid-Column Migration Driven by Photoisomerization
摘要： Droplet manipulation by light-induced isomerization was numerically demonstrated and investigated regarding the driving mechanism. Such a non-invasive manipulation of a droplet in a microchannel can be realized, for example, by the use of watery solution of photoresponsive surfactant that exhibits the isomerization. Due to variable fluid properties between the cis and trans isomers, one-side light irradiation on a liquid column in a tube would lead to some kind of imbalance between the two ends of the liquid column and then drive droplet migration. The present numerical simulations of air–liquid two-phase flow and its scalar transport of the isomer, considering the variable static contact angle, agreed quantitatively with the experimental results in terms of the migration speed. This fact supports the contention that the droplet migration is more likely to be driven by an imbalance in the wettability, or the contact angle. The migration speed was found to be less dependent on the liquid-column length, but proportional to the tube diameter.
关键词： photochemical reaction,non-invasive control,wettability,surface tension,microfluidics,computational fluid dynamics,lab-on-a-chip,droplet manipulation,two-phase flow,photoresponsible surfactant
更新于2025-09-09 09:28:46
-
Surfactant-Assisted Synthesis of Monodisperse Methylammonium Lead Iodide Perovskite Nanocrystals
摘要： Lead iodide based perovskites are promising optoelectronic materials ideal for solar cells. Recently emerged perovskite nanocrystals (NCs) offer more advantages including improved size-tunable band gap, structural stability, and solvent-based processing. Here we report a simple surfactant-assisted two-step synthesis to produce monodisperse PbI2 NCs which are then converted to methylammonium lead iodide perovskite NCs. Based on electron microscopy characterization, these NCs showed competitive monodispersity. Combined results from X-ray diffraction patterns, optical absorption, and photoluminescence confirmed the formation of high quality methylammonium lead iodide perovskite NCs. More importantly, by avoiding the use of hard-to-remove chemicals, the resulted perovskite NCs can be readily integrated in applications, especially solar cells through versatile solution/colloidal-based methods.
关键词： Surfactant,Perovskite,Nanoparticle,Methylammonium Lead Iodide,Micelle,Nanocrystal
更新于2025-09-04 15:30:14