Studies on the Effect of the Capping Materials on the Spherical Gold Nanoparticles Catalytic Activity

Seoudi, R.; Said, Doaa A.

doi:10.4236/wjnse.2011.12008

Cited by 45 publications

(31 citation statements)

References 39 publications

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“…This band decreased slightly with increased reduction time and became stable after 45 min without change. This result is in agreement with the previous work by Seoudi et al [33] and Rashid et al (2006) [34].…”

Section: Uv-vis Spectra Of Agnpssupporting

confidence: 83%

Preparation and Characterization of Silver Nanoparticles and Their Use in Catalytic Reduction of 4-Nitrophenol

Al-Marhaby¹,

Seoudi²

2016

WJNSE

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Silver nanoparticles of various sizes were prepared at room temperature using silver nitrate as a precursor, various molar ratios of sodium citrate as a surfactant stabilizing material and sodium borohydride as a reducing agent. The morphology, distribution and sphericity of the particles were assessed in images from a transmission electron microscope (TEM). The sizes of the particles were calculated as being 9, 11 and 14 nm. The effects of the particles' sizes on the plasmon bands were confirmed by ultraviolet-visible spectra measurements. The prepared samples were applied in photo catalysis of 4-Nitrophenol (4-NP), and the rate constant was determined as 0.05 s −1 , 0.0015 s −1 and 0.00021 s −1 for particles of 9 nm, 11 nm and 14 nm, respectively. Due to their high surface energy, the smaller particle sizes were more active in the photo catalytic application.

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Section: Uv-vis Spectra Of Agnpssupporting

confidence: 83%

Preparation and Characterization of Silver Nanoparticles and Their Use in Catalytic Reduction of 4-Nitrophenol

Al-Marhaby¹,

Seoudi²

2016

WJNSE

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“…Figure A shows the plot of change in the values of C t /C 0 with respect to time, in which the linear fitting of the data point is not observed and thus, the reaction does not follows the zero‐order kinetics with any of the three studied concentration of AuNPs. Moreover, Figure B shows the plot of ln(C t /C 0 ) with respect to time, in which the linear fitting of the data points can be easily observed and thus the reaction follows the first‐order kinetics in all the studied concentration . The k 1 values calculated from the respective fitting parameters are 0.243 min −1 , 0.374 min −1 and 0.666 min −1 respectively for the above mentioned concentration of Citrate‐AuNPs (see Table I).…”

Section: Resultsmentioning

confidence: 97%

Modulating the Catalytic Activity of Gold Nanoparticles through Surface Tailoring

Satapathy

Mohanta

2016

ChemistrySelect

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The present work describes the catalytic activity of gold nanoparticles towards the reduction of 4‐nitrophenol and their modulation through surface tailoring using various organic ligands. One step protocol is used to prepare CTAB capped gold nanoparticles of size 15 ± 2 nm and the catalysis reaction using these particles simultaneously follow both zero‐order and first‐order reaction kinetics. The zero‐order rate constant, k0=0.418 mol lit−1 min−1 and first‐order rate constant, k1=0.938 min−1 is achieved just by using 8 nM of gold catalyst. On the other hand citrate capped gold nanoparticles of similar sizes (13 ± 3 nm) follow only the first‐order kinetics with k1=0.243 min−1, which is about four times less compared to CTAB capped gold nanoparticles. Moreover, the reaction kinetics is changed to zero‐order rate with k0=0.345 mol lit−1 min−1 simply by replacing citrate with CTAB on the gold nanoparticles surface. On the other hand, replacing the citrate with PVP on the nanoparticles surface, the reaction rate still follows the first‐order kinetics, but with two‐fold increase in the rate constant with k1=0.587 min−1. Further, silica coating of the CTAB capped gold nanoparticles and their use as catalyst for 4‐nitrphenol reduction exclusively follows the zero‐order kinetics with k0=0.305 mol lit−1 min−1 and are better recyclable upto five cycles without affecting their conversion efficiency.

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“…An aqueous solution of 4-Nitrophenol exhibits two absorption peaks at 226 and 317 nm corresponding to *π→π (from the ring of phenol) and *π→n (from lone pair of electron in the oxygen and nitrogen atom) represented by curve 1 in Figure 11A [34]. After the addition of NaBH 4 , color change from light yellow to yellowish green confirmed by UV-Vis spectra shows a shift in absorption peak from 317 to 400 nm which is due to the generation of 4-nitrophenolate anions in the reaction system as reported in literature [7,13,35].…”

Section: Catalytic Activitymentioning

confidence: 99%

Mimosa pudica Flower Extract Mediated Green Synthesis of Gold Nanoparticles

Mapala¹,

Pattabi²

2017

NanoWorld J

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The use of Mimosa pudica flower extract in the synthesis of highly stable gold nanoparticles (AuNPs) is reported here. On treatment of aqueous chloroauric acid with crude aqueous extract of Mimosa pudica flowers, rapid reduction of Au 3+ ions at room temperature was observed without the need of any additional reducing or stabilizing agent. The synthesized AuNPs were characterized by UV-Vis spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS) and Zeta potential, X-Ray Diffraction (XRD) and Fourier Transform Infra-Red (FTIR) spectroscopy. UV-Vis studies indicated the formation of AuNPs. The AuNPs were almost spherical in shape with an average particle size of 24 nm as determined by FESEM, TEM and DLS particle size analysis. XRD studies and high resolution TEM images ascertained the crystalline nature of the AuNPs. FTIR analysis of flower extract and AuNPs showed the possibility of phenolic group as responsible for the reduction of Au 3+. The stability of the AuNPs was analyzed by Zeta potential measurements. A negative Zeta potential value of -33.4 mV proved the stability of the AuNPs. The as synthesized AuNPs exhibited good catalytic activity in the model reduction reaction of 4-Nitrophenol to 4-Aminophenol.

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Studies on the Effect of the Capping Materials on the Spherical Gold Nanoparticles Catalytic Activity

Cited by 45 publications

References 39 publications

Preparation and Characterization of Silver Nanoparticles and Their Use in Catalytic Reduction of 4-Nitrophenol

Preparation and Characterization of Silver Nanoparticles and Their Use in Catalytic Reduction of 4-Nitrophenol

Modulating the Catalytic Activity of Gold Nanoparticles through Surface Tailoring

Mimosa pudica Flower Extract Mediated Green Synthesis of Gold Nanoparticles

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