scholarly journals The role of OH− in the formation of highly selective gold nanowires at extreme pH: multi-fold enhancement in the rate of the catalytic reduction reaction by gold nanowires

2017 ◽  
Vol 19 (7) ◽  
pp. 5077-5090 ◽  
Author(s):  
Riham El Kurdi ◽  
Digambara Patra
Keyword(s):  
Gold Nanoparticles ◽  
Growth Mechanism ◽  
Catalytic Reduction ◽  
Reduction Reaction ◽  
Gold Nanowires ◽  
Au Nps

Illustration (not to scale) of the growth mechanism of gold nanoparticles (Au NPs) at pH 4 to 11 (left) and gold nanowires (Au NWs) at pH 13 (right), by reducing Au3+ to Au0 using curcumin in CTAB media in the presence of Ag+.

scholarly journals Tuning and tracking the growth of gold nanoparticles synthesized using binary surfactant mixtures

2020 ◽  
Vol 2 (5) ◽  
pp. 1980-1992
Author(s):  
Karthik Raghunathan ◽  
Jibin Antony ◽  
Sarmad Munir ◽  
Jens-Petter Andreassen ◽  
Sulalit Bandyopadhyay
Keyword(s):  
Gold Nanoparticles ◽  
Growth Mechanism ◽  
Surfactant Mixtures ◽  
Au Nps ◽  
Synthesis Parameters ◽  
First Time ◽  
Shape Transitions

The effects of synthesis parameters on the shape of gold nanoparticles (Au NPs) and their growth are investigated. A ternary space to study their shape transitions is reported for the first time. A growth mechanism based on supersaturation is proposed.

Ficus carica Linn (Dumur) Fruit Extract Mediated Green Synthesis of Gold Nanoparticles and its Application in Catalytic Reduction

2017 ◽  
Vol 1 (3) ◽  
Author(s):  
Shib Shankar Dash ◽  
Braja Gopal Bag ◽  
Abhisek Midya
Keyword(s):  
Gold Nanoparticles ◽  
Room Temperature ◽  
Catalytic Reduction ◽  
Plant Secondary Metabolites ◽  
Reduction Reaction ◽  
Ficus Carica ◽  
Resonance Spectroscopy ◽  
Fruit Extract ◽  
Efficient Catalyst ◽  
Sodium Borohydride Reduction

The fruit extract of Ficus carica Linn (Dumur) is rich in different types of plant secondary metabolites such as terpenoids, polyphenols including flavanoids, etc. We have demonstrated the use of the fruit extract for the synthesis of gold nanoparticles in water at room temperature under very mild conditions. There was no need of additional stabilizing or capping agents and the synthesis of the gold nanoparticles was complete in several minutes. The gold nanoparticles were characterized by HRTEM, EDX, SAED, Surface Plasmon Resonance Spectroscopy and X-Ray diffraction studies. The freshly prepared gold nanoparticles have been used as an efficient catalyst for the sodium borohydride reduction of 4-nitrophenol to 4-aminophenol in water at room temperature and the kinetics of the reduction reaction have been studied spectrophotometrically.

Chemical Availability of Bromide Dictates CsPbBr3 Nanocrystal Growth

2019 ◽  
Author(s):  
Je-Ruei Wen ◽  
Benjamin Roman ◽  
Freddy Rodriguez Ortiz ◽  
Noel Mireles Villegas ◽  
Nicholas Porcellino ◽  
...  
Keyword(s):  
Reaction Time ◽  
Growth Mechanism ◽  
Chemical Control ◽  
Critical Role ◽  
Phase Evolution ◽  
Detailed Understanding ◽  
Semiconductor Nanocrystal ◽  
Nanocrystal Growth ◽  
Chemical Availability

Lack of detailed understanding of the growth mechanism of CsPbBr3 nanocrystals has hindered sophisticated morphological and chemical control of this important emerging optoelectronic material. Here, we have elucidated the growth mechanism by slowing the reaction kinetics. When 1-bromohexane is used as an alternative halide source, bromide is slowly released into the reaction mixture, extending the reaction time from ~3 seconds to greater than 20 minutes. This enables us to monitor the phase evolution of products over the course of reaction, revealing that CsBr is the initial species formed, followed by Cs4PbBr6, and finally CsPbBr3. Further, formation of monodisperse CsBr nanocrystals is demonstrated in a bromide-deficient and lead-abundant solution. The CsBr can only be transformed into CsPbBr3 nanocubes if additional bromide is added. Our results indicate a fundamentally different growth mechanism for CsPbBr3 in comparison with more established semiconductor nanocrystal systems and reveal the critical role of the chemical availability of bromide for the growth reactions.<br>

Facile Synthesis of Cu2O nanoparticle-loaded Carbon Nanotubes Composite Catalysts for Reduction of 4-Nitrophenol

2020 ◽  
Vol 16 (4) ◽  
pp. 617-624 ◽  
Author(s):  
Yao Feng ◽  
Ran Wang ◽  
Juanjuan Yin ◽  
Fangke Zhan ◽  
Kaiyue Chen ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Mechanical Stability ◽  
Catalytic Reduction ◽  
High Surface ◽  
High Surface Area ◽  
Reduction Reaction ◽  
Cycle Performance ◽  
Simple Method ◽  
Composite Catalysts ◽  
Cu2o Nanoparticles

Background: 4-nitrophenol (4-NP) is one of the pollutants in sewage and harmful to human health and the environment. Cu is a non-noble metal with catalytic reduction effect on nitro compounds, and.has the advantages of simple preparation, abundant reserves, and low price. Carbon nanotubes (CNT) are widely used for substrate due to their excellent mechanical stability and high surface area. In this study, a simple method to prepare CNT-Cu2O by controlling different reaction time was reported. The prepared nanocomposites were used to catalyze 4-NP. Methods: CNTs and CuCl2 solution were put into a beaker, and then ascorbic acid and NaOH were added while continuously stirring. The reaction was carried out for a sufficiently long period of time at 60°C. The prepared samples were dried in a vacuum at 50°C for 48 h after washing with ethyl alcohol and deionized water. Results: Nanostructures of these composites were characterized by scanning electron microscope and transmission electron microscopy techniques, and the results at a magnification of 200 nanometers showed that Cu2O was distributed on the surface of the CNTs. In addition, X-ray diffraction was performed to further confirm the formation of Cu2O nanoparticles. The results of ultraviolet spectrophotometry showed that the catalytic effect of the compound on 4-NP was obvious. Conclusions: CNTs acted as a huge template for loading Cu2O nanoparticles, which could improve the stability and cycle performance of Cu2O. The formation of nanoparticles was greatly affected by temperature and the appropriate concentration, showing great reducibility for the 4-NP reduction reaction.

scholarly journals Easy and fast in-situ functionalization of exfoliated 2D black phosphorus with gold nanoparticles

2021 ◽  
Author(s):  
Salvatore Moschetto ◽  
Andrea Ienco ◽  
Gabriele Manca ◽  
Manuel Serrano-Ruiz ◽  
Maurizio Peruzzini ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Black Phosphorus ◽  
Au Nps ◽  
In Situ Functionalization

Heterostructures of single- and few-layer black phosphorus (2D bP) functionalized with gold nanoparticles (Au NPs) have been recently reported in the literature, exploiting their intriguing properties and biocompatibility for catalytic,...

In-situ stabilization of silver nanoparticles in polymer hydrogels for enhanced catalytic reduction of macro and micro pollutants

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Luqman Ali Shah ◽  
Rida Javed ◽  
Mohammad Siddiq ◽  
Iram BiBi ◽  
Ishrat Jamil ◽  
...  
Keyword(s):  
Catalytic Reduction ◽  
Thermo Gravimetric Analysis ◽  
Activation Parameters ◽  
Reduction Reaction ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
In Situ Stabilization ◽  
Hybrid Hydrogels ◽  
Kinetics Of

AbstractThe in-situ stabilization of Ag nanoparticles is carried out by the use of reducing agent and synthesized three different types of hydrogen (anionic, cationic, and neutral) template. The morphology, constitution and thermal stability of the synthesized pure and Ag-entrapped hybrid hydrogels were efficiently confirmed using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and thermo gravimetric analysis (TGA). The prepared hybrid hydrogels were used in the decolorization of methylene blue (MB) and azo dyes congo red (CR), methyl Orange (MO), and reduction of 4-nitrophenol (4-NP) and nitrobenzene (NB) by an electron donor NaBH4. The kinetics of the reduction reaction was also assessed to determine the activation parameters. The hybrid hydrogen catalysts were recovered by filtration and used continuously up to six times with 98% conversion of pollutants without substantial loss in catalytic activity. It was observed that these types of hydrogel systems can be used for the conversion of pollutants from waste water into useful products.

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