scholarly journals pH Dependence of Size Control in Gold Nanoparticles Synthesized at Room Temperature

2018 ◽  
Vol 34 (5) ◽  
pp. 2305-2312 ◽  
Author(s):  
Shohifah Annur ◽  
Sri Juari Santosa ◽  
Nurul Hidayat Aprilita
Keyword(s):  
Gold Nanoparticles ◽  
Ascorbic Acid ◽  
Room Temperature ◽  
Ph Dependence ◽  
Size Control ◽  
Spherical Shape ◽  
Alkaline Condition ◽  
Transmission Electron ◽  
Particle Size Analyzer ◽  
Spherical Gold Nanoparticles

We have developed the spherical gold nanoparticles (AuNPs) with different size at room temperature using L-ascorbic acid as a reducing agent. Controlling pH of L-ascorbic acid from 2.0 to 10.0 caused the decreasing of AuNPs size when measured using particle size analyzer. The alkaline condition leads to increase the reactivity of L-ascorbic acid even at room temperature. The homogeneous AuNPs were achieved even the synthesis was conducted at different pH of L-ascorbic acid (pH 2.0 to 12.0). The investigation using Transmission Electron Microscopy (TEM) confirmed that AuNPs performed a spherical shape. SEM-EDX measurement performed a strong characteristic peak of Au appeared at 2.0 keV. This research could be used to control of AuNPs size when synthesized at room temperature. The AuNPs obtained at optimum condition was stable up to 3 months.

Effect of Gold Nanoparticles Size on Detection of Methylphosphonic Acid Hydrolysis Product of Nerve Agent

2021 ◽  
Vol 25 (7) ◽  
pp. 1-7
Author(s):  
Fellyzra Elvya Pojol ◽  
Buong Woei Chieng ◽  
Keat Khim Ong ◽  
Rashid Jahwarhar Izuan Abd ◽  
Mohd Junaedy Osman ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Inverse Method ◽  
Direct Method ◽  
Hydrolysis Product ◽  
Spherical Shape ◽  
Methylphosphonic Acid ◽  
Visible Spectroscopy ◽  
Transmission Electron ◽  
Citrate Reduction ◽  
Chloride Trihydrate

Citrate reduction of gold (III) chloride trihydrate (HAuCl4) is commonly used method to synthesise citrate-capped gold nanoparticles (cit-AuNPs). In this study, the sequence of reagents addition was modified (“inverse” method) to synthesise smaller size of cit-AuNPs than the standard Turkevich method (“direct” method). Ultraviolet-visible spectroscopy (UV-vis) and field emission transmission electron microscopy (FETEM) confirmed the formation of cit-AuNPs. The cit-AuNPs synthesized using “inverse” method are smaller in size (14.0 ± 3.03 nm) with uniform spherical shape compared to “direct” method (23.5 ± 7.52 nm). Smaller particles size of cit-AuNPs provide higher efficiency and sensitivity for detection of methylphosphonic acid (MPA) via colorimetric incorporated with image processing with a linear range from 2.5 to 12.5 mM and a low detection limit of 6.28 mM at shorter detection period (24 to 30 s).

Preparation of Green Nanosilver by Ascorbic Acid and its Spectral Properties

2013 ◽  
Vol 749 ◽  
pp. 503-506
Author(s):  
Yang He Luo ◽  
Chun Ming Wang ◽  
Wen Qing Yin ◽  
Ai Hui Liang
Keyword(s):  
Ascorbic Acid ◽  
Spectral Properties ◽  
Room Temperature ◽  
Rayleigh Scattering ◽  
Resonance Rayleigh Scattering ◽  
Visible Spectroscopy ◽  
Laser Scattering ◽  
Transmission Electron ◽  
Uv Visible ◽  
Strong Absorption Peak

In the presence of stabilizer of citrate and room temperature, stable green nanosilver sol was prepared by reduction of AgNO3by ascorbic acid. It was characterized by UV-visible spectroscopy, resonance Rayleigh scattering (RRS) spectroscopy, laser scattering and transmission electron microscopy. Results showed that the nanosilver sol exhibited a RRS peak at 496 nm, a strong absorption peak at 414 nm and the particle size is 12 nm.

Influence of the Surfactant on the CdTe Nanomaterials Morphology

2011 ◽  
Vol 287-290 ◽  
pp. 294-297
Author(s):  
Cui Zhi Dong ◽  
Li Fang Zhang ◽  
Xiao Yan Wang ◽  
Ming Xi Zhang ◽  
Zhi Min Cui ◽  
...  
Keyword(s):  
Room Temperature ◽  
Chemical Properties ◽  
Semiconductor Materials ◽  
Alkaline Condition ◽  
Microemulsion System ◽  
X Ray ◽  
Cdte Nanoparticles ◽  
Ctab Concentration ◽  
Transmission Electron ◽  
And Chemical Properties

Because of the good photoelectric learning properties and chemical properties, CdTe nanocrystalline as an important Ⅱ-Ⅵ clan semiconductor materials has been used in LEDs, photonics, in aspects of materials and biomarker and so on. W/O microemulsion method has the peculiarity of tester simpleness, easy manipulation, room temperature react etc. In this paper CdTe nanoparticles was synthesized in CTAB/cyclohexane/isobutanol/water quatemary microemulsion system in alkaline condition and nitrogen. The morphology of the final products were characterized by X-ray power diffraction, transmission electron microscopy. according to the means, this paper researches the effect of surfactant contentration to morphology. The result is that the different morphology can be obtained through the different CTAB concentration. Finally, according to TEM chart, this paper infers the formation mechanism of the CdTe.

Preparation of Cellulose Acetate Ultra-Fine Fibers Containing Quasi-Spherical Gold Nanoparticles by Electrospinning Method

2011 ◽  
Vol 391-392 ◽  
pp. 400-403
Author(s):  
Dong Mei Zhao ◽  
Li Guo Sun ◽  
Li Li Lv ◽  
Jian Li
Keyword(s):  
Electron Microscopy ◽  
Gold Nanoparticles ◽  
Cellulose Acetate ◽  
Trisodium Citrate ◽  
X Ray Diffraction ◽  
Au Nps ◽  
Transmission Electron ◽  
Electrospinning Method ◽  
Before And After ◽  
Spherical Gold Nanoparticles

Quasi-spherical gold nanoparticles(Au NPs) prepared by trisodium citrate reduction of HAuCl4were dispersed into cellulose acetate(CA) ultra-fine fibers by electrospinning. The optical properties of Au NPs before and after electrospinning were measured by UV-vis spectrometer. The morphology and distribution of Au NPs in CA ultra-fine fibers were observed by transmission electron microscopy (TEM). The morphology and diameter of Au NPs/CA fibers were studied by scanning electron microscopy (SEM). The crystallinity change of CA fiber before and after adding Au NPs was characterized by X-ray diffraction (XRD).

scholarly journals Green Nanoparticles for Mosquito Control

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Namita Soni ◽  
Soam Prakash
Keyword(s):  
Gold Nanoparticles ◽  
Mosquito Control ◽  
Spherical Shape ◽  
Probit Analysis ◽  
Bark Extract ◽  
Green Method ◽  
Silver And Gold Nanoparticles ◽  
Transmission Electron ◽  
Uv Visible ◽  
Filariasis Vector

Here, we have used the green method for synthesis of silver and gold nanoparticles. In the present study the silver (Ag) and gold (Au) nanoparticles (NPs) were synthesized by using the aqueous bark extract of Indian spice dalchini (Cinnamomum zeylanicum) (C. zyelanicumorC. verumJ. Presl). Additionally, we have used these synthesized nanoparticles for mosquito control. The larvicidal activity has been tested against the malaria vectorAnopheles stephensiand filariasis vectorCulex quinquefasciatus. The results were obtained using UV-visible spectrophotometer and the images were recorded with a transmission electron microscope (TEM). The efficacy tests were then performed at different concentrations and varying numbers of hours by probit analysis. The synthesized AgNPs were in spherical shape and average sizes (11.77 nm AgNPs and 46.48 nm AuNPs). The larvae ofAn. stephensiwere found highly susceptible to the synthesized AgNPs and AuNPs than theCx. quinquefasciatus. These results suggest that theC. zeylanicumsynthesized silver and gold nanoparticles have the potential to be used as an ideal ecofriendly approach for the control of mosquito.

Synthesis and Properties of Monometallic and Bimetallic Silver and Gold Nanoparticles

2009 ◽  
Vol 1207 ◽  
Author(s):  
Xavier Enrique Guerrero Dib ◽  
Ubaldo Ortiz-Méndez ◽  
Selene Sepúlveda-Guzmán ◽  
Oxana Vasilievna Kharisova ◽  
Domingo Ferrer ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Ascorbic Acid ◽  
High Resolution ◽  
Cetyltrimethylammonium Bromide ◽  
Bimetallic Nanoparticles ◽  
Spherical Shape ◽  
Metal Salts ◽  
Elemental Mapping ◽  
Actual Distribution ◽  
Successive Reduction

AbstractSynthesis of Au, Ag monometallic, and Au-Ag bimetallic nanoparticles have been synthesized by successive reduction of metal salts with ascorbic acid on prefabricated seeds in the presence of cetyltrimethylammonium bromide (C16H33)N(CH3)3Br (CTAB), as a cationic surfactant, is presented in this paper. This coverage method for the prefabricated seeds is uniform, although in some cases deviations from a spherical shape are observed with the formation of nanorods or nanoprisms. Results using high-resolution STEM-XEDS elemental mapping suggest that the actual distribution of the two metals within the multilayer spheres may involve partial alloying of the metals.

Synthesis of Gold Nanoparticles Using Glutamic Acid as a Reductor and Capping Agent

2020 ◽  
Vol 840 ◽  
pp. 472-477
Author(s):  
Naura Nadhifah ◽  
Wening Rara Pratita ◽  
Eko Sri Kunarti ◽  
Nuryono Nuryono ◽  
Sri Juari Santosa
Keyword(s):  
Gold Nanoparticles ◽  
Acid Solution ◽  
Glutamic Acid ◽  
Color Change ◽  
Reaction Times ◽  
Chloroauric Acid ◽  
Optimum Synthesis ◽  
Transmission Electron ◽  
Particle Size Analyzer ◽  
Uv Visible

The synthesis of gold nanoparticles (AuNPs) was carried out by reacting chloroauric acid [AuCl4]‒ and glutamic acid solution in a water bath at 80 °C. The reaction was confirmed by the color change from colorless solution into pink. Various concentrations of the glutamic acid solution, reaction times and pH were examined to determine the optimum condition of AuNPs synthesis. The AuNPs colloid was characterized by UV-Visible spectrophotometer at wavelength 350-800 nm, particle size analyzer (PSA) and transmission electron microscope (TEM). The optimum synthesis condition for obtained [AuCl4]‒ was 4 mM glutamic acid solution at pH 11 and 60 min reaction. TEM results showed that the particles were round in shape with the article size indicated by PSA was 40 nm.

Study of Antioxidant Property of the Endosperm Extract of Borassus flabellifer (Taal) and its use in the green synthesis of Gold nanoparticles

2017 ◽  
Vol 1 (2) ◽  
Author(s):  
Sk Nurul Hasan ◽  
Braja Gopal Bag
Keyword(s):  
Gold Nanoparticles ◽  
Room Temperature ◽  
Antioxidant Property ◽  
Resonance Spectroscopy ◽  
Surface Plasmon Resonance Spectroscopy ◽  
Dpph Radical ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ftir Studies ◽  
Transmission Electron

The antioxidant activity of the endosperm extract of Borassus flabellifer (commonly known as Taal) has been studied against a long lived 2,2-diphenylpicrylhydrazyl (DPPH) radical at room temperature. The phytochemicals present in the endosperm extract have been utilized for the synthesis of stable gold nanoparticles at room temperature under very mild conditions. The synthesized gold nanoparticles were characterized by Surface Plasmon Resonance spectroscopy, High resolution transmission electron microscopy, X-Ray diffraction and FTIR studies and a mechanism for the synthesis of stabilized gold nanoparticles has been proposed.

Synthesis of SrTiO3 Nanoparticles by a Simple Sonochemical Method

2012 ◽  
Vol 424-425 ◽  
pp. 949-952
Author(s):  
Yu Jiang Wang ◽  
Lin Lin Yang ◽  
Yong Gang Wang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Powder Diffraction ◽  
Room Temperature ◽  
Spherical Shape ◽  
Sonochemical Method ◽  
X Ray ◽  
Transmission Electron ◽  
Ultrasonic Time ◽  
Pure Phase

SrTiO3 nanoparticles were successfully synthesized by a sonochemical method at room temperature. The as-prepared powders were characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM), and exhibited a pure phase SrTiO3 with a perovskite structure about 20nm in size with uniform and nearly spherical shape. It is found that the size of the obtained nanoparticles increased with prolonging the ultrasonic time.

Controlled Growth of Gold Nanoparticles on Silica Nanowires

2005 ◽  
Vol 20 (11) ◽  
pp. 3021-3027 ◽  
Author(s):  
Aaron D. LaLonde ◽  
M. Grant Norton ◽  
Daqing Zhang ◽  
Devananda Gangadean ◽  
Abdullah Alkhateeb ◽  
...  
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Substrate Temperature ◽  
Size Distribution ◽  
Surface Diffusion ◽  
Ostwald Ripening ◽  
Size Control ◽  
Chemical Vapor ◽  
Chamber Pressure ◽  
Transmission Electron

Production of gold nanoparticles with the specific goal of particle size control has been investigated by systematic variation of chamber pressure and substrate temperature. Gold nanoparticles have been synthesized on SiO2 nanowires by plasma-enhanced chemical vapor deposition. Determination of particle size and particle size distribution was done using transmission electron microscopy. Average nanoparticle diameters were between 4 and 12 nm, with particle size increasing as substrate temperature increased from 573 to 873 K. A bimodal size distribution was observed at temperatures ≥723 K indicating Ostwald ripening dominated by surface diffusion. The activation energy for surface diffusion of gold on SiO2 was determined to be 10.4 kJ/mol. Particle sizes were found to go through a maximum with increases in chamber pressure. Competition between diffusion within the vapor and dissociation of the precursor caused the pressure effect.

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