scholarly journals Green synthesis: Proposed mechanism and factors influencing the synthesis of platinum nanoparticles

2020 ◽  
Vol 9 (1) ◽  
pp. 386-398 ◽  
Author(s):  
Mahmood S. Jameel ◽  
Azlan Abdul Aziz ◽  
Mohammed Ali Dheyab
Keyword(s):  
Green Synthesis ◽  
Reaction Temperature ◽  
Platinum Nanoparticles ◽  
Energy Requirement ◽  
Average Particle Size ◽  
High Energy ◽  
Energy Utilization ◽  
Critical Parameters ◽  
Synthesis Process ◽  
Average Particle

AbstractPlatinum nanoparticles (Pt NPs) have attracted interest in catalysis and biomedical applications due to their unique structural, optical, and catalytic properties. However, the conventional synthesis of Pt NPs using the chemical and physical methods is constrained by the use of harmful and costly chemicals, intricate preparation requirement, and high energy utilization. Hence, this review emphasizes on the green synthesis of Pt NPs using plant extracts as an alternative approach due to its simplicity, convenience, inexpensiveness, easy scalability, low energy requirement, environmental friendliness, and minimum usage of hazardous materials and maximized efficiency of the synthesis process. The underlying complex processes that cover the green synthesis (biosynthesis) of Pt NPs were reviewed. This review affirms the effects of different critical parameters (pH, reaction temperature, reaction time, and biomass dosage) on the size and shape of the synthesized Pt NPs. For instance, the average particle size of Pt NPs was reported to decrease with increasing pH, reaction temperature, and concentration of plant extract.

Green synthesis and characterization of ANbO3 (A = Na, K) nanopowders fabricated using a biopolymer

2017 ◽  
Vol 31 (27) ◽  
pp. 1750194
Author(s):  
Gh. H. Khorrami ◽  
M. Mousavi ◽  
S. A. Khayatian ◽  
A. Kompany ◽  
A. Khorsand Zak
Keyword(s):  
Green Synthesis ◽  
Average Particle Size ◽  
Synthesis Process ◽  
Bandgap Energy ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Optical Bandgap Energy ◽  
Scherrer Formula

Lead-free sodium niobate (NaNbO3, NN) and potassium niobate (KNbO3, KN) nanopowders were successfully synthesized by a simple and green synthesis process in gelatin media. Gelatin, which is a biopolymer, was used as stabilizer. In order to determine the lowest calcination temperature needed to obtain pure NN and KN nanopowders, the produced gels were analyzed by thermogravometric analyzer (TGA). The produced gels were calcined at 500[Formula: see text]C and 600[Formula: see text]C. The structural and optical properties of the prepared powders were examined using X-ray diffraction (XRD) technique, transmission electron microscopy (TEM), and UV–Vis spectroscopy. The XRD results revealed that pure phase NN and KN nanopowders were formed at low temperature calcination of 500[Formula: see text]C and 600[Formula: see text]C, respectively. The Scherrer formula and size-strain plot (SSP) method were employed to estimate crystallite size and lattice strain of the samples. The TEM images show that the NN and KN samples calcined at 600[Formula: see text]C have cubic shape with an average particle size of 60.95 and 39.29 nm, respectively. The optical bandgap energy of the samples was calculated using UV–Vis diffused reflectance spectra of the samples and Kubelka–Munck relation.

scholarly journals High-Temperature Synthesis of Metal–Matrix Composites (Ni-Ti)-TiB2

2021 ◽  
Vol 11 (5) ◽  
pp. 2426
Author(s):  
Vladimir Promakhov ◽  
Alexey Matveev ◽  
Nikita Schulz ◽  
Mikhail Grigoriev ◽  
Andrey Olisov ◽  
...  
Keyword(s):  
High Temperature ◽  
Composite Materials ◽  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Metal Matrix ◽  
Average Particle Size ◽  
Synthesis Process ◽  
Average Particle ◽  
Temperature Synthesis ◽  
High Temperature Synthesis

Currently, metal–matrix composite materials are some of the most promising types of materials, and they combine the advantages of a metal matrix and reinforcing particles/fibres. Within the framework of this article, the high-temperature synthesis of metal–matrix composite materials based on the (Ni-Ti)-TiB2 system was studied. The selected approaches make it possible to obtain composite materials of various compositions without contamination and with a high degree of energy efficiency during production processes. Combustion processes in the samples of a 63.5 wt.% NiB + 36.5 wt.% Ti mixture and the phase composition and structure of the synthesis products were researched. It has been established that the synthesis process in the samples proceeds via the spin combustion mechanism. It has been shown that self-propagating high-temperature synthesis (SHS) powder particles have a composite structure and consist of a Ni-Ti matrix and TiB2 reinforcement inclusions that are uniformly distributed inside it. The inclusion size lies in the range between 0.1 and 4 µm, and the average particle size is 0.57 µm. The obtained metal-matrix composite materials can be used in additive manufacturing technologies as ligatures for heat-resistant alloys, as well as for the synthesis of composites using traditional methods of powder metallurgy.

Nanosized Hydroxyapatite Powder Synthesized from Eggshell and Phosphoric Acid

2007 ◽  
Vol 7 (11) ◽  
pp. 4061-4064 ◽  
Author(s):  
Sang-Jin Lee ◽  
Young-Soo Yoon ◽  
Myung-Hyun Lee ◽  
Nam-Sik Oh
Keyword(s):  
Phosphoric Acid ◽  
Heating Temperature ◽  
Average Particle Size ◽  
Stoichiometric Composition ◽  
Synthesis Process ◽  
Average Particle ◽  
Mixing Ratio ◽  
Powder Synthesis ◽  
Chemical Route ◽  
Milling Method

The present research describes synthesis of highly sinterable, nano-sized hydroxyapatite (HAp) powders using a wet chemical route with recycled eggshell and phosphoric acid as calcium and phosphorous sources. The raw eggshell was easily turned to CaO by the calcining process, and phosphoric acid was mixed with the calcined eggshell by the wet, ball-milling method. The crystalline development and microstructures of the synthesized powders and sintered samples were examined by X-ray diffractometry and scanning electron microscopy, respectively. The observed phases on the powder synthesis process were dependent on the mixing ratio (wt%) of the calcined eggshell to phosphoric acid and the heating temperature. The ball-milled, nano-sized HAp powder, which has an average particle size of 70 nm, was fully densified at 1300 °C for 1h. The Ca/P ratio for stoichiometric composition of HAp was controlled by adjustment of the mixing ratio.

scholarly journals A Comparative Study of Nanostructures of CuO/Cu2O Fabricated via Potentiostatic and Galvanostatic Anodization

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
S. Mary Margaret ◽  
Albin John P. Paul Winston ◽  
S. Muthupandi ◽  
P. Shobha ◽  
P. Sagayaraj
Keyword(s):  
Thermal Stability ◽  
Comparative Study ◽  
Aqueous Electrolyte ◽  
Average Particle Size ◽  
Xrd Analysis ◽  
Molecular Vibration ◽  
Synthesis Process ◽  
Average Particle ◽  
Good Crystallinity ◽  
Cu Foil

A detailed comparative study on the synthesis process of coral-like CuO/Cu2O nanorods (NRs) and nanopolycrystals (NPCs) fabricated on Cu foil employing aqueous electrolyte via potentiostatic (POT) and galvanostatic (GAL) modes is discussed. The structural, morphological, thermal, compositional, and molecular vibration of the prepared CuO/Cu2O nanostructures was characterized by XRD, HRSEM, TG/DTA, FTIR, and EDX techniques. XRD analysis confirmed the crystalline phase of the formation of monoclinic CuO and cubic Cu2O nanostructures with well-defined morphology. The average particle size was found to be 21.52 nm and 26.59 nm for NRs (POT) and NPCs (GAL), respectively, and this result is corroborated from the HRSEM analysis. POT synthesized nanoparticle depicted a higher thermal stability up to 600°C implying that the potentiostatically grown coral-like NRs exhibit a good crystallinity and well-ordered morphology.

Preparation and Magnetic Properties of Carbon Encapsulated Fe-Cu Alloy Nanoparticles

2010 ◽  
Vol 177 ◽  
pp. 673-676 ◽  
Author(s):  
Jun Xue ◽  
Hou Kui Xiang ◽  
Hong Qiao Ding ◽  
Shu Li Pang ◽  
Xue Hua Wang ◽  
...  
Keyword(s):  
Magnetic Measurement ◽  
Average Particle Size ◽  
Soft Magnetic Property ◽  
Copper Nitrate ◽  
Synthesis Process ◽  
Ferric Nitrate ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cu Alloy

Carbon encapsulated Fe-Cu alloys nanoparticles were synthesized by using ferric nitrate, copper nitrate as metal sources and using sucrose as carbon source. The synthesis process involved a step of hydrazine hydrate reduction in alcohol solution and a step of annealing carbonization. The as-prepared samples were characterized by X-ray diffraction technique, X-ray energy dispersion spectrograph, trans- mission electron microscopy and Raman spectroscopy. The results showed the sample was core / shell structure, the metalic core was crystalline FeCu4 alloy, the shell was amorphous carbon, and the average particle size was about 51nm. The magnetic measurement by using a vibrating sample magnetometer revealed that the sample has ultra-soft magnetic property with the saturation magnetization Ms of 13.01 emu/g, residual magnetization Mr of 0.37 emu/g and coercive forces Hc of 54.43 Oe at room temperature.

Dual synthesis of Silver and Iron oxide nanoparticles from edible greens Amaranthus Viridis and their in vitro antioxidant activity and antimicrobial studies

2021 ◽  
Vol 10 ◽  
Author(s):  
Venkata Subbaiah Kotakadi ◽  
Bhulakshmi Kolapalli ◽  
Susmila Aparna Gaddam ◽  
Sai Gopal Divi Venkata Ramana
Keyword(s):  
Antioxidant Activity ◽  
Particle Size ◽  
Green Synthesis ◽  
Metallic Nanoparticles ◽  
Iron Nanoparticles ◽  
Average Particle Size ◽  
Leafy Vegetable ◽  
Size Analysis ◽  
Average Particle

Background: There is an increasing commercial demand for nanoparticles due to their wide applicability in various areas such as chemistry, catalysis, energy and medicine. Metallic nanoparticles are traditionally synthesized by wet chemical techniques where the chemicals used are quite often toxic and flammable. Objective: In the present study, we described a simple, cost effective and environmentally-friendly technique for green synthesis of silver and iron nanoparticles by using the aqueous extract of leafy vegetable Amaranthus viridis as a reducing agent. Methods: The silver and Iron nanoparticles (Av-AgNPs, Av-IONPs) were characterized by different spectral methods. The surface Plasmon resonance spectrums of Av-AgNPs, Av-IONPs were recorded at 422nm and 261nm. The Scanning electron microscopy (SEM) analysis reveals that the Av-AgNPs, Av-IONPs are roughly spherical in shape. Energy dispersive absorption spectroscopy (EDAX) of biosynthesized Av-AgNPs, Av-IONPs indicates the reduction of silver ions to elemental silver and iron ions to elemental iron. Results: The particle size analysis of Av-AgNPs and Av-IONPs was carried out by Dynamic light scattering (DLS) method the results reveal that both Av-AgNPs and Av-IONPs were polydispered in nature. The average particle size of Av-AgNPs is 55.8 nm with a polydispered index (PI) of 0.297, similarly the average particle size of Av-IONPs is 80.6 nm with an polydispered index (PI) of 0.469. Zeta-potential of Av-AgNPs was detected at -24.6 mV and Av-IONPs were detected at 28.8 mV, the result reveals that they high stability due their high negative charge and positive charge respectively. The dual synthesized Av-AgNPs, Av-IONPs exhibits excellent antioxidant activity by DPPH, H2O2 and NO methods. DPPH was proven to be the best when compared with the other two methods. The biosynthesized Av-AgNPs, Av-IONPs proved to have very good antimicrobial activity against gram +ve and gram –ve bacteria. Conclusion: when compared with standard antibiotic. There were several reports on green synthesis of metal nanoparticles using various plant parts, but here edible leafy vegetable Amaranthus viridis was used for biosynthesis of both Av-AgNPs and Av-IONPs.

Preparation of Nanosized Barium Titanate Powder by a Direct Reactive Precipitation Method

2013 ◽  
Vol 690-693 ◽  
pp. 454-457
Author(s):  
Hong Bo Li ◽  
Shu Yan Wu ◽  
Jing Wang ◽  
Chun Jie Li
Keyword(s):  
Particle Size ◽  
Reaction Temperature ◽  
Surface Active Agent ◽  
Average Particle Size ◽  
Active Agent ◽  
Precipitation Method ◽  
Precipitation Process ◽  
Average Particle ◽  
Powder Particle Size ◽  
Powder Morphology

Columnar crystaldendriteequiaxial dendritescolumnar crystalNanosized powder was synthesized by direct-reactive precipitation process using a stoichiometrical mixture of TiCl4, BaCl2 as the reactants while NaOH as precipitant. Under the ratio of Ba to Ti is 1.02, PH=13, three reaction temperature of 70°C, 80°C and 90°C were conducted respectively. Morphology and phase structure of powder were investigated, and the influence of reaction temperature on powder morphology was discussed. The result indicates that synthesized powder is single cubic BaTiO3 and contains no impurities. BaTiO3 powders generally show spherical, and average particle size decreases with increasing reaction temperature. When reaction temperature is 80°C, BaTiO3 powder has best uniformity and dispersivity with the diameter of 80-100nm. The influence of reaction temperature on powder particle size can be attributed to the corporate contribution of nucleation and growth rate. Polyglycol as surface active agent has a significant effect in restraining agglomeration.

Control of average particle size of carbon aerogel supported platinum nanoparticles by supercritical deposition

2017 ◽  
Vol 245 ◽  
pp. 94-103 ◽  
Author(s):  
Şansım Bengisu Barım ◽  
Ayşe Bayrakçeken ◽  
Selmi Erim Bozbağ ◽  
Lichun Zhang ◽  
Rıza Kızılel ◽  
...  
Keyword(s):  
Particle Size ◽  
Platinum Nanoparticles ◽  
Average Particle Size ◽  
Carbon Aerogel ◽  
Average Particle ◽  
Supported Platinum ◽  
Supercritical Deposition

scholarly journals Green Synthesis of Highly Concentrated and Stable Colloidal Dispersion of Core-Shell Silver Nanoparticles (AgNPs-Shell) and their Antimicrobial and Ultra-high Catalytic Properties

2021 ◽  
Author(s):  
Azam Ali ◽  
Mehrukh Zehravi ◽  
Muhammad Humble Khalid Treen ◽  
Jiri Militky ◽  
Fiaz Hussain ◽  
...  
Keyword(s):  
Green Synthesis ◽  
Tannic Acid ◽  
Large Scale ◽  
Catalytic Properties ◽  
Average Particle Size ◽  
Colloidal Dispersion ◽  
Alkaline Condition ◽  
Core Shell ◽  
Average Particle ◽  
One Pot

The versatile one-pot green synthesis of a highly concentrated and stable colloidal dispersion of AgNPs was carried out using the self-assembled tannic acid without using any other hazardous chemicals. Tannic acid (Plant-based polyphenol) was used as a reducing and stabilizing agent for silver nitrate in a mild alkaline condition. The synthesized AgNPs were characterized for their concentration, capping, size distribution, and shape. The experimental results confirmed the successful synthesis of nearly spherical and highly concentrated (2281 ppm) AgNPs, capped with poly-tannic acid (AgNPs-PTA). The average particle size of AgNPs-PTA was found 9.90 ± 1.60 nm. The colloidal dispersion of synthesized nanoparticles was observed stable for more than 15 months in the ambient environment (25 oC, 65 % relative humidity). The synthesized AgNPs-PTA showed an effective antimicrobial activity against Staphylococcus Aureus Escherichia coli. Ag-PTA also exhibited enhanced catalytic properties. It reduces 4-nitrophenol into 4-aminophenol in the presence of NaBH4 with a normalized rate constant (Knor = K/m) of 615.04 mL·s-1·mg-1. Furthermore, AgNPs-PTA were stable for more than 15 months under ambient conditions. The unique core-shell structure and ease of synthesis render the synthesized nanoparticles superior to others, with potential for large-scale applications, especially in the field of catalysis and biomedical.

scholarly journals An Efficient Microwave-Assisted Synthesis Method of Novel Bi2O3 Nanostructure and Its Application As a High-Performance Nanocatalyst in Preparing Benzylidene Barbituric Acid Derivatives

2021 ◽  
Author(s):  
Mahdieh Yahyazadehfar ◽  
Enayatollah Sheikhhosseini ◽  
Sayed Ali Ahmadi ◽  
Dadkhoda Ghazanfari
Keyword(s):  
Barbituric Acid ◽  
Aqueous Media ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Synthesis Process ◽  
Microwave Assisted Synthesis ◽  
Average Particle ◽  
Short Period ◽  
High Yields ◽  
Barbituric Acid Derivatives

Abstract In this study, controllable and optimal microwave irradiation has been used to synthesize the novel nanostructures of Bi2O3 under environmental conditions. The final products had a thermal stability of 210 °C, an average particle size distribution of 85 nm, and surface area of 783 m2/g. The high thermodynamic stability of Bi2O3 nanostructures were confirmed by TG and DSC analyses. The nanostructure nature of compounds, most importantly, the use of effective, cost effective and rapid synthesis route of microwave have created significant physiochemical properties in the Bi2O3 products. These unexpected properties have made the possibility of potentials application of these products in various fields, especially in nanocatalyst applications. It is well-documented that, as Lewis acid, bismuth nanocatalyst exhibits a great catalytic activity for the green synthesis of some bio-active barbituric acid derivatives using precursors with electron-donating or –withdrawing nature in high yields (80-98%). After incorporating this catalyst into the aqueous media, all the reactions were completed within 2-3 min at room temperature. The main advantages of this method are practical facility, the availability of starting materials, and low costs besides the catalyst reusability. Additionally, the catalyst synthesis process may be carried in the aqueous media during a short period with medium to high yields. The obtained results have opened a new window for development of a novel nanocatalyst with practical application.

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