Growth Process Of Nanoparticles Research Articles

Design of ZIF-8/ion copolymer hierarchically porous material: Coordination effect on the adsorption and diffusion for carbon dioxide

The novel CO2 adsorbent (ZPMAC) was constructed by a facile in-situ growth of ZIF-8 onto the surface of a mesoporous amino-functionalized ion copolymer (PMAC). The existence of coordination effect between Zn2+ from ZIF-8 and nitrogen atom from the amino-alkyl chain in PMAC changed the pore structure of substrate for enhancing the amount of CO2 capture and accelerated the rate of CO2 adsorption. The ion copolymer PMAC, pristine ZIF-8 and hierarchically porous hybrid material ZPMAC were characterized by SEM, TEM, TGA, N2 adsorption-desorption, FT-IR, XRD, UV, and XPS techniques. It was observed that ZIF-8 loaded on the surface of PMAC uniformly and tightly. In the growth process of ZIF-8 nanoparticles, zinc ions were firstly coordinated with nitrogen atoms of the amino-alkyl chain in PMAC sample, and subsequently reacted with 2-methylimizadole to generate ZIF-8 nanoparticles. Obviously, the surface areas of ZPMAC increased and smaller peak value of micropore distribution was generated by the strong coordination interaction between ZIF-8 and PMAC after ZIF-8 modified. Meanwhile, the appearance of hierarchically porous structure was conducive to the transportation and adsorption of CO2 molecules, thus enhancing the amount of CO2 capture and the rate of adsorption effectively. This study was intended to design a new kind of hybrid materials by the means of in-situ growth of MOF materials onto the IL-type polymers and further study the influences of the structure and properties of ionic-type hybrid materials on the absorption capacity to meet the requirements of various applications.

Continuous preparation of structure-controlled carbon nanoparticle via arc plasma and the reinforcement of polymeric composites

Environmental-friendly continuous process of manufacturing structure-controlled carbon black (CB) nanoparticles has been developed by the combination of advantages of alternative-current (AC) gliding arc plasma and direct-current (DC) arc discharge plasma. In this process, methane was first decomposed in the low temperature AC gliding arc plasma and then further thermally pyrolyzed in the DC arc discharge plasma area. CB was generated in the AC arc plasma area and then continued to grow or surface modified by DC arc plasma according to different arc positions, which was determined by the operating gas flow rate. The effects of AC arc and DC arc on the yield, size, morphology and structure of particles have been investigated. The connection of AC and DC plasma areas might cause totally different growth process of nanoparticles. Formation mechanism has been discussed based on series of physical characterizations to illustrate the different growth process. The essential properties of CB prepared by plasma have been compared with three kinds of CB purchased, and then all the CB nanoparticles have been blended with acrylonitrile-butadienestyrene/ethylene-propylene-diene monomer composites. Electrical conductivity and mechanical properties as well as the morphology of fracture surface of composites have been characterized. The results indicate that CB prepared from AC plasma process shows excellent mechanical reinforcement and CB from AC+DC plasma process owns outstanding electrical conductivity.

Carboxylated-nanoncellulose as a template for the synthesis of silver nanoprism

The features of templates, such as physical dimensions or functional groups, often affect the in situ growth process of nanoparticles. In this study, a rapid thermal synthesis method was adopted for the synthesis of Ag nanoprisms (AgNPRs) on cellulose nanofibrils (CNF), which were obtained via defibrillations of holocellulose. In comparison, holocellulose and pure cellulose also were used for the attempted synthesis of AgNPRs. The produced nanocomposites were examined for their optical and physical properties using ultraviolet-visible spectroscopy, transmission electron microscopy and X-ray diffraction. The results demonstrate that the reduced of the fibres into nanosize and carboxylate functional groups present on the cellulosic template affects the formation of AgNPRs, with which CNF is able to form AgNPRs. The surface-enhanced Raman scattering (SERS) activity of the CNF-AgNPRs composite was studied and exhibited a higher enhancement, compared to the spherical AgNPs-anchored CNF. The CNF prepared from carboxylated holocellulose not only served as nanoparticles support for the SERS application, it also facilitated the formation of AgNPRs that resulted in a better enhancement SERS signal.

Sol-gel synthesis of CoFe2O4:SiO2 nanocomposites – insights into the thermal decomposition process of precursors

Succinate precursors dispersed in the silica matrix were obtained by sol-gel synthesis using Co and Fe nitrates, 1,4-butanediol and tetraethyl orthosilicate. The thermal decomposition of Co and Fe succinates into cobalt ferrite (CoFe2O4) at different CoFe2O4:SiO2 molar percentages was studied by thermal analysis, Fourier transformed infrared spectrometry (FT-IR) and X-ray diffraction. The morphology of nanoparticles was identified by transmission and scanning electron microscopy. The formation of succinates in the pores of the silica matrix and their decomposition to CoFe2O4 spinel was confirmed by the FT-IR spectra. The nanocrystallites size (7–33nm) increases with the decrease of SiO2 content, suggesting that the growth process of nanoparticles is reduced in the presence of silica matrix.

Mode transition in dusty micro-plasma driven by pulsed radio-frequency source in C2H2/Ar mixture**Project supported by the Natural Science Foundation of Heilongjiang Province, China (Grant Nos. A2015011 and A2015010), the Postdoctoral Scientific Research Developmental Fund of Heilongjiang Province, China (Grant No. LBH-Q14159), the National Natural Science Foundation of China (Grant Nos. 11404180 and 11405092), and the Program for Young Teachers Scientific

Physical qualities of dusty plasma in the pulsed radio-frequency C2H2/Ar microdischarges are carefully investigated by a one-dimensional hydrodynamic model and aerosol dynamics model. Since the thermophoretic force has a great effect on the nanoparticle density spatial distribution, the neutral gas energy equation is taken into accounted. The effects of pulse parameters (dust ratio, modulation frequency) on the nanoparticle formation and growth process are mainly discussed. The calculation results show that, as the duty ratio increases, the mode transition from the sheath oscillation (α regime) to the secondary electron heating (γ regime) occurred, which is quite different from the conventional pulsed discharge. Moreover, the effect of modulation frequency on the width of sheath and plasma density is analyzed. Compared with the H2CC ions, the modulation frequency effect on the nanoparticles density becomes more prominent.

Size-dependent photoluminescent property of hybrid nanoparticlesconsisted with YVO4:Eu3+ and gold

The hydrothermally synthesizedYVO4:Eu3+nanophosphors were mixed with gold nanoparticles with different sizes to form hybrid nanoparticles. The microstructure and luminescent properties of all hybrid nanoparticles were charaterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Visible absorption spectrum (UV-Vis), and photoluminescence (PL) spectroscopy. The growth process of gold nanoparticles prepared by seeding growth method was discussed firstly. Furthermore, the effects of grain size of gold nanoparticles on the fluorescent property of hybrid nanoparticles were investigated in detail. All the emission spectra presented the characteristic red emission of Eu3+. The emission intensity of hybrid nanoparticles was increasing with the growing of gold nanoparticles. The influential mechanism was discussed as well.

Numerical investigation on the growth process and size distribution of nanoparticles obtained through electrical explosion of aluminum wire

Numerical investigations on the formation process and the final size distribution of nanoparticles during electrical explosion of Al wire are carried out. Firstly, the formation of the atomic vapor clusters is investigated. It indicates that the Al wire does not reach its atomization conditions. The size of the atomic vapor clusters is obtained, and it increases with the temperature at explosion. Then the growth process of Al nanoparticles from the formed atomic vapor clusters is modeled and the size distribution is predicted. The size distribution at different temperatures indicates that the growth process of Al nanoparticles becomes inactive gradually as the temperature decreases. The investigation of the size distribution under different cooling rates indicates that the bigger cooling rate is favorable for the formation of Al nanoparticles with smaller size dispersion and lower average dimension. The size distribution of Al nanoparticles obtained by the model is qualitatively consistent with the experimental data, which demonstrates the feasibility of this model.

A strategy for fabrication of controllable 3D pattern containing clusters and nanoparticles inside a solid material.

Directly controlling the growth process of clusters and nanoparticles is an effective way to tune their specific properties, which has been considered as a significant issue lying at the heart of nanotechnology. For technological applications, great strides have been made in the assembly of clusters and nanoparticles. However, controllable synthesis of clusters and nanoparticles inside a bulk solid-state medium remains a tremendous challenge, which is important for integrated devices. Here we report a strategy for space-selective control of elemental tellurium (Te) precipitation as clusters or nanoparticles in glass by femtosecond (fs) laser irradiation. After irradiation by a 1 kHz fs laser at 800 nm, Te2 clusters, which emit near-infrared (NIR) light, are observed at the focal point of the laser beam inside the glass sample. By shifting the repetition rate to 250 kHz, a temperature field forms around the focal area that facilitates transformation of Te clusters into nanoparticles. Raman mapping shows that the clusters are localized in the center of the laser-induced microstructure, while the nanoparticles exhibit an annular distribution. The possible mechanisms of generation and distribution of different species are discussed. We have also demonstrated optical data storage and embedded micro-grating by using this technique.

纳米材料原位生长表征技术的研究进展

纳米技术的关键是按人们的意志直接操控单个原子、分子或原子团、分子团，实现纳米材料的可控合成，制备具有特定功能的材料。纳米材料原位生长研究可获得体系中纳米粒子生长过程的动态瞬时信息，继而掌握纳米材料生长特征模式和生长参数，该研究对实现纳米材料可控生长具有重要意义，本文就纳米材料原位生长研究的技术方法进行概述，并对其发展前景进行展望。 The key of nanotechnology is operating single atom, molecules or the groups of atoms and mole-cules directly according to the aspiration of the people, realizing the controlled synthesis of na-nomaterials and synthetizing materials with specific functions. In-situ growth research of nano-materials can obtain the dynamic transient information of the growth process of nanoparticles in the system, and then grasp the growth characteristic and parameters of nanomaterials. It is significant for controllable synthesis of nanomaterials. In this paper, many different technical approaches which can be applied to trace the in-situ growth of nanomaterials are summarized, and the development prospect was forecasted.

Titanate Nanorods Modified with Nanocrystalline ZnS Particles and Their Photocatalytic Activity on Pollutant Removal

Aiming to produce materials with enhanced photocatalytic properties, the synthesis of new crystalline nanocomposites by combining titanate nanorods (TNR) with ZnS nanocrystallites is described in this work. The TNR modification was accomplished by an in situ nucleation and growth process of ZnS nanoparticles. Zinc diethyldithiocarbamate was used as the metal chalcogenide precursor. The prepared materials were structural, morphological and optical characterized by X-ray diffraction, transmission electron microscopy and high resolution transmission electron microscopy, energy dispersive spectroscopy and powder diffuse reflectance spectra. Crystalline ZnS nanoparticles were obtained as a homogeneous and continuous layer, covering completely the TNR surface. The application of these new nanocomposite materials on photocatalytic degradation of pollutants was investigated. First, the evaluation of hydroxyl radical formation, using the terephthalic acid as probe, was studied. Afterwards, the adsorption and photodegradation of safranine-T, used here as a model pollutant molecule, was investigated. The obtained data indicate that the prepared nanocomposites have potential to be used as photocatalysts for organic pollutant removal. The best removal results (97% removal) were obtained using the 0.01ZnS/HTNR sample as catalyst (0.2 g/L; 10 ppm safranin-T solution) with a combination of a low dye adsorption (20%) and a high dye photocatalytic degradation (77%).

Nucleation and solid–liquid interfacial energy of Li nanoparticles: A molecular dynamics study

AbstractThe nucleation and growth processes of lithium nanoparticles are simulated by molecular dynamics and embedded atom method. A critical temperature dividing, shrinking, or growing of lithium nanoparticles is determined. The linear relationship between the depression of the melting point of the lithium nanoparticle and the reciprocal of the critical nuclei is determined when the critical nuclei are between 1.0 and 2.0 nm. Solid–liquid interfacial energies of lithium nanoparticles are estimated from the Gibbs–Thomson effect. These results are consistent with the experimental values of other metals.

Synthesis and Characterization of Nanofibrous Polyaniline Thin Film Prepared by Novel Atmospheric Pressure Plasma Polymerization Technique.

This work presents a study on the preparation of plasma-polymerized aniline (pPANI) nanofibers and nanoparticles by an intense plasma cloud type atmospheric pressure plasma jets (iPC-APPJ) device with a single bundle of three glass tubes. The nano size polymer was obtained at a sinusoidal wave with a peak value of 8 kV and a frequency of 26 kHz under ambient air. Discharge currents, photo-sensor amplifier, and optical emission spectrometer (OES) techniques were used to analyze the plasma produced from the iPC-APPJ device. Field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), gas chromatography-mass spectrometry (GC-MS), and gel permeation chromatography (GPC) techniques were used to analyze the pPANI. FE-SEM and TEM results show that pPANI has nanofibers, nanoparticles morphology, and polycrystalline characteristics. The FT-IR and GC-MS analysis show the characteristic polyaniline peaks with evidence that some quinone and benzene rings are broken by the discharge energy. GPC results show that pPANI has high molecular weight (Mw), about 533 kDa with 1.9 polydispersity index (PDI). This study contributes to a better understanding on the novel growth process and synthesis of uniform polyaniline nanofibers and nanoparticles with high molecular weights using the simple atmospheric pressure plasma polymerization technique.

Mechanistic Insight into DNA-Guided Control of Nanoparticle Morphologies.

Although shapes and surface characteristics of nanoparticles are known to play important roles in defining their properties, it remains challenging to fine-tune the morphologies systematically and predictably. Recently, we have shown that DNA molecules can serve as programmable ligands to fine-tune the morphologies of nanomaterials. Despite this discovery, the mechanism of how the morphology can be controlled and the roles of the DNA molecules in contributing to such control are not understood. We herein report mechanistic investigation of DNA-mediated morphological evolution of gold nanoprism seeds into nonagon, hexagon, and six-pointed stars, some of which display rough surfaces, in the presence of homo-oligomeric T30, G20, C30, and A30. The growth, elucidated through various analytical methods including UV-vis, SEM, TEM, zeta potential, fluorescence, and cyclic voltammetry, is found to occur in two stages: control of shape, followed by control of thickness. A careful analysis of diffraction patterns of the nanoprism seeds as well as the resulting intermediate shapes by TEM allowed us to deduce the exact sequence of shape evolution. Through systematic comparison of the nanoparticle growth process, the DNA molecules were found to play important roles by influencing diffusion of the Au precursor to the seed and modulating the growth through differences in DNA desorption, density, and mobility on the seed surface. These insights into the mechanism of DNA-guided control of nanomaterial morphologies provide deeper understanding of the interactions between the DNA and nanomaterials and will allow better control of the shapes and surface properties of many nanomaterials.

Study of the growth of hydrophilic iron oxide nanoparticles obtained via the non-aqueous sol–gel method

The growth process of hydrophilic iron oxide nanoparticles synthesized via the non-aqueous sol–gel method using TEG as high-boiling solvent has been characterized. A model of the growth process is presented, based on a combination of analytical methods, especially XRD, SAXS and TGA. In contrast to previously studied particles synthesized in benzyl alcohol, which grow via nucleation, particles synthesized in TEG grow via a sol–gel-like process. In a first step, an amorphous network is formed, and subsequently, during the compaction of the network, crystalline particles are obtained. The influence of the structural properties on the magnetic behavior was identified by combining various spectroscopic methods.

Synthesis of nanoparticles in helium droplets-A characterization comparing mass-spectra and electron microscopy data.

Micrometer sized helium droplets provide an extraordinary environment for the growth of nanoparticles. The method promises great potential for the preparation of core-shell particles as well as one-dimensional nanostructures, which agglomerate along quantum vortices, without involving solvents, ligands, or additives. Using a new apparatus, which enables us to record mass spectra of heavy dopant clusters (>10(4) amu) and to produce samples for transmission electron microscopy simultaneously, we synthesize bare and bimetallic nanoparticles consisting of various materials (Au, Ni, Cr, and Ag). We present a systematical study of the growth process of clusters and nanoparticles inside the helium droplets, which can be described with a simple theoretical model.

Impact of heating mode in synthesis of monodisperse iron-oxide nanoparticles via oleate decomposition

The present work introduces the optimization of a synthetic procedure for oleate-coated iron-oxide nanoparticles by the thermal decomposition of Fe oleate dried at 30 and 70 °C in high-boiling organic solvents. The attention is focused on the temperature of the thermal decomposition, the nature of organic solvent, heating rate and the mode of the heating. In particular, heating on Wood alloy with simultaneous bubbling of argon through the reaction mixture versus the heating on mantel with magnetic stirring is highlighted as a route to improve the monodispersity of the nanoparticles. The effect of heating mode and rate on the nanoparticles size is estimated. The obtained tendencies point to the heating mode and rate as additional factors affecting the kinetic separation between nucleation and nanoparticle growth processes.

Synthesis of metal-carbon nanoparticles in pulsed UV-photolysis of Fe(CO)5-CCl4 mixtures at room temperature

Synthesis of iron-carbon nanoparticles in joint photolysis of iron pentacarbonyl (Fe(CO)5) and carbon tetrachloride (CCl4) has been studied. When mixtures containing iron pentacarbonyl and CCl4 are exposed to UV light, Fe(CO)5 molecules decompose to yield an atomic vapor of iron with well-known and easily controlled parameters, whereas CCl4 molecules decompose to give CCl3 radicals. A pulsed Nd:YAG laser (fourth harmonic, 266 nm) served as a source of light. The growth process of nanoparticles in condensation of supersaturated vapors was monitored by the laser extinction method; nanoparticle samples were examined with an atomic-force microscope. It was found that the concentration of the CCl4 additive affects the manner in which the optical properties of nanoparticles synthesized in a binary mixture change relative to the properties of nanoparticles synthesized in photolysis of pure Fe(CO)5, which indicates that a carbon shell grows on the surface of iron nanoparticles.

Revealing Growth Schemes of Nanoparticles in Atomic Resolution: Mapping Stacking Fault Formation and Distribution

Controlling the growth process of inorganic nanoparticles, especially the kinetically driven ones, is crucial for designing tailor-made nanoparticles for various applications. Specifically, controlling the formation of stacking faults in semiconductor quantum dots is necessary, since stacking faults were associated with inferior optical performance. Ensemble techniques, such as XRD powder diffraction and optical absorption, can be insensitive to the formation of stacking faults and in certain cases might produce misleading information. Using as a model the thoroughly studied CdSe system, we exploited the well-known unidirectional growth of the Wurtzite phase in order to follow the structural evolution of two different batches of CdSe nanoparticles. We were able to get insight on the crystal growth stages, step by step, employing high resolution electron microscopy and focal series reconstruction. The different kinetics of the two variants were monitored using a statistical approach. The same approach can be used to provide atomic-scale information for any system exhibiting unidirectional growth.

Cu Electro-Redox on the Surface of Single-Walled Carbon Nanotube Network

In this study, pristine single-walled carbon nanotube (SWNT) networks were used as the templates for the copper nanoparticle electrodeposition and the electro-redox process were investigated. The working electrode, SWNT networks, was prepared via catalyzed chemical vapor deposition on insulating SiO2 surface and was characterized by scanning electron microscopy, thermogravimetric analysis, transmission electron microscopy, X-ray photoelectron spectroscopy, and linear sweep analysis. In the static experiment (batch reactor), deposition of high-density Cu nanoparticles on the SWNTs was observed via atomic force microscopy and field emission scanning electron microscopy, over extensive periods (45s), with contiguous formation from the boundary to further distances. Mass transfer was quantitatively analyzed via chronoamperometry and normal pulse voltammetry and physical adsorption of the copper ions were observed to demonstrate a positive temperature-dependence. A range of Cu ion concentrations was used to analyzed the electron transfer till the mass transfer and adsorption processed were saturated and the electron transfer rates were determined to be 1.5×1017 and 2.6×1018e-s-1m-2 at anode potentials of 0.3 and 0.5V,repectively. All these above approaches described the nucleation and growth processes of Cu nanoparticles on SWNTs during electrodeposition. In comparison with Ag and Pt growth reported before, Cu nanoparticles grew less rapidly and progressively. The dynamic experiment (filter reactor) is on-going based on results of the static one. Our work is promising to provide a new route to recover copper from waste mining water.

Prediction of Nonradical Au(0)-Containing Precursors in Nanoparticle Growth Processes

This density functional theory (DFT) investigation examines the formation of nonradical Au(0) species from the reduction of Au(I) species. The Au(I) complexes of interest are AuCl2(-), AuBr2(-), AuI2(-), AuClPH3, and AuCl(H)SCH3(-), which are precursors for gold nanoparticle and cluster formation. Reaction of two of the Au(I) species with a hydride results in ejection of two of the ligands and formation of Au2 with two ligands still attached. AuX2(-) (where X = Cl, Br, or I) reactions eject two halides and form Au2X2(2-). AuClL(-) (where L = PH3, HSCH3, or SCH3(-)) reactions can eject either chloride, HCl, PH3, HSCH3, or SCH3(-) and form Au(0)L2(q-) or Au(0)ClL(q-) (q = 0, 1, 2). The Au2Cl2(2-) complex can further react with AuCl2(-), which forms Au3Cl3(2-) and a chloride anion. The new Au3Cl3(2-) species can then react with AuCl2(-) or Au2Cl2(2-) or with another Au3Cl3(2-). Larger clusters can be formed from these precursors. In this work, reactions in both methanol and benzene solvents are considered as models for one-phase and two-phase gold nanoparticle growth processes. Overall, this investigation shows how Au(0)-containing species can be formed without assuming the formation of Au(0) atoms (radical species).