A Simple and Green Method for Synthesis of Ag and Au Nanoparticles using Biopolymers and Sugars as Reducing Agent

2012 ◽  
Vol 1386 ◽  
Author(s):  
Germán Ayala ◽  
Luci Cristina de Oliveira Vercik ◽  
Thiago Antônio Villa Menezes ◽  
Andrés Vercik
Keyword(s):  
Silver Nitrate ◽  
Au Nanoparticles ◽  
Low Ph ◽  
Repulsive Force ◽  
Reducing Agent ◽  
Absorption Peak ◽  
Chloroauric Acid ◽  
Gold Salt ◽  
Colloid Stability ◽  
Green Method

ABSTRACTIn this work we study the effect of different reducing agent (chitosan, starch and sugars) on to synthesis of silver (AgNPs) and gold (AuNPs) nanoparticles by reduction of silver nitrate (AgNO3) and chloroauric acid (HAuCl4), respectively. The plasmon absorption peak between 419 - 434 nm, measured using a UV-Vis spectrophotometer indicates the existence of AgNPs, this reaction was favored by the increase of temperature with optimal results at 90°C. Synthesis of AuNPs was only obtained using chitosan as reducing agent, the use of solutions of starch and sugars allows the reduction of the gold salt present in the chloroauric acid, however the low pH of the solutions creates thermodynamic instabilities for the AuNP synthesis, due to low repulsive force for colloid stability.

scholarly journals GREEN SYNTHESIS OF SILVER NANOPARTICLES USING SAGO (METROXYLON SAGU) VIA AUTOCLAVING METHOD

2018 ◽  
Vol 19 (1) ◽  
pp. 178-184
Author(s):  
Aliyah Jamaludin ◽  
Che Ku Mohammad Faizal
Keyword(s):  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Silver Nitrate ◽  
Large Scale ◽  
Reducing Agent ◽  
Average Particle ◽  
Particle Sizes ◽  
Green Method ◽  
Metroxylon Sagu

Sago (metroxylon sagu) is a polysaccharide bio resource, which is biodegradable and low in toxicity that can be found in large scale in Mukah, Sarawak.  A simple green method of synthesizing silver nanoparticles (AgNPs) has been developed using sago dissolved in water as the reducing agent. The mixture of dissolved sago and silver nitrate (AgNO3) were autoclaved at 121 °C for 20 minutes. The size, morphology and structures of the AgNPs formed in the sago solution were investigated through UV-Vis spectrophotemeter, XRD and FESEM analysis. The synthesized AgNPs were spherical in shape and well distributed with average particle sizes of 19.3 ± 2.7 nm.ABSTRAK: Sago (Pokok Rumbia) adalah sumber bio polisakarida yang bioterurai dan rendah ketoksikan yang boleh didapati dalam skala yang besar di Mukah, Sarawak. Satu kaedah hijau yang mudah untuk mensintesis nanopartikel perak telah dihasilkan dengan menggunakan sagu yang larut dalam air sebagai ejen penurunan. Campuran sagu yang dilarutkan dan perak nitrat (AgNO3) telah autoklaf pada suhu 121°C selama 20 minit. Saiz, morfologi dan struktur nanopartikel perak yang terhasil di dalam larutan sago telah disiasat melalui analisis spektrofotometer UV-Vis, XRD dan FESEM. Nanopartikel perak yang dihasilkan adalah berbentuk bulat dengan purata saiz partikel 19.3 ± 2.7 nm.

Synthesis and Properties of Au Nanoparticles with Various Sizes

2013 ◽  
Vol 710 ◽  
pp. 117-121 ◽  
Author(s):  
Yuan Na Zhu ◽  
Yong Qiang Cao ◽  
Ai Yu Zhang ◽  
Ping Yang
Keyword(s):  
Raman Scattering ◽  
Au Nanoparticles ◽  
Particle Diameter ◽  
Trisodium Citrate ◽  
Reducing Agent ◽  
Molar Ratio ◽  
Chloroauric Acid ◽  
Au Nps ◽  
Transmission Electron ◽  
Nir Absorption

Properties of Au nanoparticles (NPs) caused by various sizes (5-12 nm) were studied in this article. Au NPs capped with citrate of various sizes were synthesized by two methods including trisodium citrate dihydrate reduction of chloroauric acid tetrahydrate and sodium borohydride reducion of chloroauric acid tetrahydrate. Au NPs were characterized and measured by using transmission electron microscope (TEM), UV-vis-NIR absorption spectroscopy, and surface Raman scattering. The results of experiment indicated that the size of Au NPs was related to the type of reducing agent and molar ratio of reducing agent and chloroauric acid. The weaker the reducing capacity of the reducing agent or the lower the molar ratio, the bigger the size of Au NPs is. The max wavelength of absorption peak for the citrate-capped Au NPs is red-shifted with the increase of particle diameter. Raman scattering observed from Au NPs of various sizes is found to be NP size-dependent. It is clear that the bigger Au NPs are more apparent in the Raman scattering determination. Size-tunable Au NPs should be crucial for biosensors, particularly as Raman-tag particles.

Preparation and Characterization of Fe3O4@Au Nanoparticles Used as Precursor of Ferrofluids

2010 ◽  
Vol 177 ◽  
pp. 415-417 ◽  
Author(s):  
De Cai Li ◽  
Zhi Li Zhang ◽  
Shao Lan Zhang
Keyword(s):  
Photoelectron Spectrum ◽  
Sodium Citrate ◽  
Au Nanoparticles ◽  
Ammonium Hydroxide ◽  
Reducing Agent ◽  
Chloroauric Acid ◽  
Fe3o4 Magnetic Nanoparticles ◽  
X Ray ◽  
Co Precipitation

The Fe3O4 magnetic nanoparticles were prepared through co-precipitation of Fe3+ and Fe2+ with ammonium hydroxide. The initially obtained Fe3O4 nanoparticles were then coated by gold in solution of chloroauric acid through connecting of 3-aminopropyropyl thriethoxysilane (3-APTES) and the obtained Fe3O4@Au nanoparticles were further characterized by X-ray photoelectron spectrum (XPS). During the process, the influences of chloroauric acid, reducing agent, coupling agent and nanoparticles of Fe3O4 were studied. The results showed that core-shell structure Fe3O4@Au particles have diameters of about 20nm in size synthesized from sodium citrate as reducing agent with 10.08 emu/g of saturation magnetization.

Application of Polycarboxylate Superplasticizer in the Concrete

2017 ◽  
Vol 898 ◽  
pp. 2076-2080 ◽  
Author(s):  
Xing Qi Huang ◽  
Xiao Rong Li ◽  
Da Wei Zhang ◽  
Chang Jun Xue ◽  
Ai Qin Zhang
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Molecular Design ◽  
High Water ◽  
Repulsive Force ◽  
Reducing Agent ◽  
Functional Design ◽  
Agent Based ◽  
Type Water ◽  
Low Dosage

Compared with the traditional water reducer, polycarboxylicwater-reducing agent exhibits the advantages of high water-reducing rate, cement paste fluidity and low slump loss, etc. The structure of polycarboxylates water reducing agent molecular is comb type. Water reducing agent can be used in the molecular design because it has high water reducing rate, low dosage, good slump stability, and have great potential in increase strength. In recent years, it has attracted many researchers' attention. Water reducing agent can block or destroy cement granular flocculation structure, through the surface function, complexation, electrostatic repulsion force and stereo repulsive force. Research on water reducing agent based on the application of poly carboxylic acid can realize functional design of water reducing agent, so as to promote the development of high-performance concrete.

Controlling the Surface Plasmon Absorption of Silver Nanoparticles via Green Synthesis Using Pennisetum purpureum Leaf Extract

2018 ◽  
Vol 772 ◽  
pp. 73-77
Author(s):  
Ruelson S. Solidum ◽  
Arnold C. Alguno ◽  
Rey Capangpangan
Keyword(s):  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Silver Nitrate ◽  
Surface Plasmon ◽  
Leaf Extract ◽  
Nitrate Solution ◽  
Silver Nitrate Solution ◽  
Absorption Peak ◽  
Plasmon Absorption ◽  
Surface Plasmon Absorption

We report on the green synthesis of silver nanoparticles utilizing theP.purpureumleaf extract. Controlling the surface plasmon absorption of silver nanoparticles was achieved by regulating the amount of extract concentration and the molarity of silver nitrate solution. The surface plasmon absorption peak is found at around 430nm. The surface plasmon absorption peak have shifted to lower wavelength as the amount of extract is increased, while plasmon absorption peak shifts on a higher wavelength as the concentration of silver nitrate is increased before it stabilized at 430nm. This can be explained in terms of the available nucleation sites promoted by the plant extract as well as the available silver ions present in silver nitrate solution.

The studies on highly concentrated complex dispersions of gold nanoparticles and temperature-sensitive nanogels and their application as new blood-vessel-embolic materials with high-resolution angiography

2014 ◽  
Vol 2 (36) ◽  
pp. 6044-6053 ◽  
Author(s):  
Yingying Ma ◽  
Jiangshan Wan ◽  
Kun Qian ◽  
Shinan Geng ◽  
Nijun He ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
High Resolution ◽  
Blood Vessel ◽  
Au Nanoparticles ◽  
Blood Pool ◽  
Temperature Sensitive ◽  
Colloid Stability ◽  
Blood Pool Imaging ◽  
Embolic Materials

High colloid stability of highly concentrated Au nanoparticles (GNPs) for use in blood-pool imaging was achieved, using p(N-isopropylacrylamide-co-butyl methylacrylate) nanogels.

scholarly journals Tapping Opportunity of Tiny-Shaped Particles and Role of Precursor in Developing Shaped Particles

NANO ◽  
2018 ◽  
Vol 13 (07) ◽  
pp. 1850073 ◽  
Author(s):  
Mubarak Ali ◽  
I-N. Lin ◽  
Chien-Jui Yeh
Keyword(s):  
Silver Nitrate ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Chloroauric Acid ◽  
Binary Composition ◽  
Gold Silver ◽  
Morphology And Structure ◽  
Specific Shape ◽  
Understanding Of Science ◽  
Hcp Structure

Metallic colloids are frequently used in industry and provide understanding of science at microns to nanometers scales along with their applicability for various technologically important applications. Present investigations deal with morphology and structure of gold, silver and their binary composition while processing certain amounts of their solutions in a newly designed process and tapping opportunities of developing tiny-shaped particles. At tuned ratio of pulse OFF to ON time and when gold solution was processed, several tiny-shaped particles developed at the solution’s surface. Such tiny particles exert force at the tip of each converting their structure of smooth element where steady-state immersing behavior directed them toward a common centre resulting into bind them for developing different geometric anisotropic shaped particles. Under identical parameters along with pulse time, processing solutions of silver nitrate and binary composition of chloroauric acid-silver nitrate result in the development of tiny particles having no specific shape where their assembling is under the mixed behavior of forces resulting in distorted particles. Elongation and deformation of gold and silver atoms while developing different structures are because of the plastically driven behavior of their electrons. In three-dimensional structures where atoms do not undergo transition to elongate, they retain the structure as it is, which is known as hcp structure or two-dimensional structure. Different nature of precursors along with morphology and structure of particles are discussed in this paper opening abundant avenues for research.

Noble metal nanoparticle-decorated TiO2 nanobelts for enhanced photocatalysis

2014 ◽  
Vol 07 (05) ◽  
pp. 1450064 ◽  
Author(s):  
Haiyan He ◽  
Ping Yang ◽  
Changchao Jia ◽  
Yanping Miao ◽  
Jie Zhao ◽  
...  
Keyword(s):  
Noble Metal ◽  
Au Nanoparticles ◽  
Acid Corrosion ◽  
Metal Nanoparticle ◽  
Noble Metal Nanoparticles ◽  
Au Nanoparticle ◽  
Chloroauric Acid ◽  
Sem Images ◽  
Photogenerated Electrons ◽  
Coarse Surface

TiO 2 nanobelts have been fabricated through a hydrothermal method and subsequently sulfuric-acid-corrosion-treated for a rough surface. Noble metal nanoparticles such as Ag and Au were deposited on the coarse surface of TiO 2 nanobelts via a coprecipitation procedure. Ag – TiO 2 nanobelts were prepared in ethanolic solution contained silver nitrate ( AgNO 3) and sodium hydroxide ( NaOH ). Au – TiO 2 nanobelts were obtained in chloroauric acid ( HAuCl 4) using sodium borohydride ( NaBH 4) as the reductant. It is confirmed by the results of XRD patterns together with the SEM images that the composite of noble metal and TiO 2 nanobelts were obtained successfully and the Ag or Au nanoparticles were well-dispersed on the TiO 2 nanobelts. Moreover, the as-prepared Ag and Au nanoparticle-decorated TiO 2 nanobelts represent an enhanced photocatalytic activity compared with pure TiO 2 nanobelts, which is due to the fact that the Ag and Au nanoparticles on the surface of TiO 2 nanobelts act as sinks for the photogenerated electrons and promote the separation of the electrons and holes.

Graphene Oxide Reduced and Dispersed by Polysaccharide

2013 ◽  
Vol 341-342 ◽  
pp. 233-236 ◽  
Author(s):  
Yong Qiang He ◽  
Ru Qiang Li ◽  
Di Wu ◽  
Yong Li Zhang ◽  
Jian Ping Gao ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Low Temperature ◽  
Reduce Graphene Oxide ◽  
Aqueous Dispersion ◽  
Reducing Agent ◽  
Reaction Conditions ◽  
Green Method ◽  
Stabilizing Agent ◽  
Optimum Reaction

An green method to reduce graphene oxide (RGO) was developed by using polysaccharide as both a reducing agent and a stabilizing agent. The RGO was characterized and the factors that affect the reduction of graphene oxide (GO) were explored to obtain optimum reaction conditions. Analysis shows that GO can be reduced at a comparatively low temperature by polysaccharide and forms a stable RGO aqueous dispersion owing to the dispersion of polysaccharide. This approach provides a new green method for GO reduction that has great value for graphene applications.

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