scholarly journals Polyaniline Nanofibers-Embedded Gold Nanoparticles Obtained by Template-Free Procedure with Immobilization Prospects

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8470
Author(s):  
Joaquín Rafael Crespo-Rosa ◽  
Alfonso Sierra-Padilla ◽  
Juan José García-Guzmán ◽  
David López-Iglesias ◽  
Dolores Bellido-Milla ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Gold Nanoparticles ◽  
Conducting Polymers ◽  
Electrochemical Impedance ◽  
High Energy ◽  
Synthesis Process ◽  
Sonochemical Method ◽  
One Pot ◽  
Short Period ◽  
Template Free

In this work, template-free nanostructured conducting polymers (nCPs)-embedded gold nanoparticles (AuNPs) from aniline, thiophene and 3,4-ethylenedioxythiophene have been prepared via a one-pot sonochemical method. The synthesis of the nanocomposite (nCPs-AuNPs) was achieved in a short period of time (5–10 min), by applying high-energy ultrasound to an aqueous mixture of a CP precursor monomer and KAuCl4, in the presence of LiClO4 as dopant. The synthesis process is simpler, greener and faster in comparison to other procedures reported in the literature. Remarkably, bulk quantities of doped polyaniline PANI-AuNPs nanofibers were obtained. Subsequently, they were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR), as well as by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). PANI-AuNPs nanofibers were also employed as immobilization matrix for a benchmark enzyme, glucose oxidase (GOX). Finally, glucose was determined in real samples of white and red wines by using the so-obtained GOX-PANI-AuNPs/Sonogel-Carbon biosensor, providing outstanding recoveries (99.54%). This work may offer important insights into the synthesis of nanostructured conducting polymers and also stimulates the exploration of the applications of these nanocomposites, especially in research fields such as (bio)sensors, catalysis and composite materials.

scholarly journals Effects of Different Surfactant Charges on the Formation of Gold Nanoparticles by the LASiS Method

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2937
Author(s):  
Muhammad Zulfajri ◽  
Wei-Jie Huang ◽  
Genin-Gary Huang ◽  
Hui-Fen Chen
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gold Nanoparticles ◽  
Laser System ◽  
Synthesis Process ◽  
Au Nps ◽  
Laser Fluences ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
532 Nm

The laser ablation synthesis in solution (LASiS) method has been widely utilized due to its significant prospects in laser microprocessing of nanomaterials. In this study, the LASiS method with the addition of different surfactant charges (cationic CTAB, nonionic TX-100, and anionic SDS) was used to produce Au NPs. An Nd:YAG laser system at 532 nm excitation with some synthetic parameters, including different laser fluences, ablation times, and surfactant concentrations was performed. The obtained Au NPs were characterized by UV-Vis spectroscopy, transmission electron microscopy, and zeta potential analyzer. The Au NPs exhibited the maximum absorption peak at around 520 nm for all samples. The color of Au NPs was changed from red to reddish by increasing the laser fluence. The surfactant charges also played different roles in the Au NPs’ growth during the synthesis process. The average sizes of Au NPs were found to be 8.5 nm, 5.5 nm, and 15.5 nm with the medium containing CTAB, TX-100, and SDS, respectively. Besides, the different surfactant charges induced different performances to protect Au NPs from agglomeration. Overall, the SDS and CTAB surfactants exhibited higher stability of the Au NPs compared to the Au NPs with TX-100 surfactant.

scholarly journals Sensitive and Selective Electrochemical Detection of Epirubicin as Anticancer Drug Based on Nickel Ferrite Decorated with Gold Nanoparticles

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1334
Author(s):  
Mohammad Mehmandoust ◽  
Nevin Erk ◽  
Ceren Karaman ◽  
Fatemeh Karimi ◽  
Sadegh Salmanpour
Keyword(s):  
Electron Microscopy ◽  
Gold Nanoparticles ◽  
Nickel Ferrite ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Differential Pulse ◽  
X Ray ◽  
Transmission Electron ◽  
The Stability ◽  
Electrochemical Electrode

The accurate and precise monitoring of epirubicin (EPR), one of the most widely used anticancer drugs, is significant for human and environmental health. In this context, we developed a highly sensitive electrochemical electrode for EPR detection based on nickel ferrite decorated with gold nanoparticles (Au@NiFe2O4) on the screen-printed electrode (SPE). Various spectral characteristic methods such as Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-Vis), energy-dispersive X-ray spectroscopy (EDX) and electrochemical impedance spectroscopy (EIS) were used to investigate the surface morphology and structure of the synthesized Au@NiFe2O4 nanocomposite. The novel decorated electrode exhibited a high electrocatalytic activity toward the electrooxidation of EPR, and a nanomolar limit of detection (5.3 nM) was estimated using differential pulse voltammetry (DPV) with linear concentration ranges from 0.01 to 0.7 and 0.7 to 3.6 µM. The stability, selectivity, repeatability reproducibility and reusability, with a very low electrode response detection limit, make it very appropriate for determining trace amounts of EPR in pharmaceutical and clinical preparations.

Facile fabrication of MnO2-embedded 3-D porous polyaniline composite hydrogel for supercapacitor electrode with high loading

2019 ◽  
Vol 32 (3) ◽  
pp. 286-295 ◽  
Author(s):  
Huabo Huang ◽  
Renpeng Chen ◽  
Shuaiyi Yang ◽  
Liang Li ◽  
Yulan Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Porous Structure ◽  
High Performance ◽  
Electrochemical Impedance ◽  
In Situ Polymerization ◽  
Composite Hydrogel ◽  
High Loading ◽  
Supercapacitor Electrode ◽  
One Pot ◽  
Charge Discharge

To obtain the promising pseudocapacitance of MnO2, the composite hydrogel of MnO2 and polyaniline (PANI) was fabricated using in situ polymerization of aniline hydrochloride in the aqueous solution containing commercial MnO2 nanoparticles and additives. Both scanning electron microscopy and transmission electron microscopy results indicated that the composite hydrogel exhibited a 3-D porous structure, within which MnO2 nanoparticles were uniformly embedded. The investigations of cyclic voltammetry, galvanostatic charge−discharge, and electrochemical impedance spectroscopy demonstrated superior supercapacitor (SC) performance of the hydrogel electrode even with high loading. The electrode with loading of 1.5 mg cm–2 showed a favorable specific capacitance (293 F g–1, 10 mV s–1), which only decreased to 258 F g–1 when the loading of the electrode was seven times higher (10.8 mg cm–2). Furthermore, the hydrogel electrode displayed good cycle stability in the acidic solution (81% capacitance retention after 1000 charge/discharge cycles). The favorable electrochemical performance of the composite hydrogel should be attributed to the fast electron/ion transport and good protection for MnO2 in the 3-D porous structure. Due to the facile one-pot synthesis and optimized nanostructure, it could be expected that MnO2-embedded 3-D porous PANI composite hydrogels have great application in the field of high-performance electrode with high loading for SCs.

Synthesis of CdWO4 Nanoflakes and Nanorods by a Sonochemical Process

2012 ◽  
Vol 174-177 ◽  
pp. 413-416
Author(s):  
Jin Liu ◽  
Lin Lin Yang ◽  
Yu Jiang Wang ◽  
Xiao Feng Wang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Early Stage ◽  
Ultrasound Irradiation ◽  
Sonochemical Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Ultrasonic Time ◽  
Template Free

CdWO4 nanoflakes and nanorods have been successfully prepared through a mild template-free sonochemical method without any surfactants. The as-prepared samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). It was found that the ultrasound irradiation played an important role in the formation of CdWO4 crystals. The results showed that CdWO4 nanoflakes were first formed at the early stage, and CdWO4 nanoflakes were transformed into nanorods as the ultrasonic time was prolonged from 0.5h to 1.5h.

scholarly journals One-pot synthesis of cellulose/MoS2 composite for efficient visible-light photocatalytic reduction of Cr(VI)

BioResources ◽  
2019 ◽  
Vol 14 (3) ◽  
pp. 6114-6133
Author(s):  
Chunxiang Lin ◽  
Yushi Liu ◽  
Qiaoquan Su ◽  
Yifan Liu ◽  
Yuancai Lv ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electrochemical Impedance ◽  
Photocatalytic Reduction ◽  
X Ray Diffraction ◽  
One Pot ◽  
Simultaneous Reduction ◽  
X Ray ◽  
Transmission Electron ◽  
Reduction Efficiency ◽  
Hole Scavenger

An effective cellulose/MoS2 (Ce/MoS2) composite was synthesized via a one-pot microwave-assisted ionic liquid method for the photocatalytic reduction of toxic Cr(VI). Effects of ionic liquids (ILs) on the MoS2 nanostructure were considered, and the obtained composite was characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectrometry (XPS), and electrochemical impedance spectroscopy (EIS). The results indicated that the MoS2 nanoplates were anchored and dispersed on the surface of the cellulose. Compared with the pristine MoS2, the support of the cellulose greatly enhanced the photocatalytic reduction efficiency of Cr(VI) ions in solution, from 65.9% to nearly 100%. The reduction mechanism was considered, and the results implied that the simultaneous reduction of Cr(VI) during the initial dark adsorption process was observed due to the effect of citric acid as a hole scavenger. Finally, regeneration tests revealed that the Ce/MoS2 composite could be recycled and reused.

Preparation of graphene/polyaniline nanocomposite by in situ intercalation polymerization and their application in anti-corrosion coatings

2019 ◽  
Vol 31 (9-10) ◽  
pp. 1226-1237 ◽  
Author(s):  
Yiyi Li ◽  
Yiting Xu ◽  
Shicheng Wang ◽  
Hongchao Wang ◽  
Meng Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electrochemical Impedance ◽  
In Situ Polymerization ◽  
Expanded Graphite ◽  
Corrosion Current ◽  
Immersion Test ◽  
Synthesis Process ◽  
Protective Mechanism ◽  
Tafel Polarization

This study reports a strategy for further simplifying the synthesis process of polyaniline-modified graphene (An/G) nanocomposite. For this purpose, the An/G nanocomposite was prepared by expanded graphite (EG) and aniline (An) via in situ polymerization. The structures and morphologies of the An/G nanocomposite were examined by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, ultraviolet–visible spectroscopy and atomic force microscopy. The results show that the An/G nanocomposite was synthesized successfully. The coatings were prepared using polyaniline (PANI) and An/G as the fillers and epoxy resin as the matrix. The anti-corrosion performance was evaluated by electrochemical impedance spectroscopy, Tafel polarization curve and salt immersion test. When An/G100 nanocomposite with a mass ratio of An to EG of 100:1 as a filler is used, the coating on the steel exhibited superior anti-corrosion effect. In particular, the impedance at 0.01 Hz of the coating with the An/G100 nanocomposite at a low loading of 2 wt% (An/G100-2) remained constant above 1 × 1010 Ω·cm2 for up to 35 days in 3.5 wt% sodium chloride solution. The Tafel plots reveal that the undamaged zone of the An/G100-2 coating possessed a high corrosion potential of −0.16 V, and the corrosion current density was only 1.5 × 10−11 A cm−2. The protective mechanism of graphene and PANI is discussed.

Can the Degree of Crystallinity of Ball Milled Mg2Ni Intermetallic Compound Decide its Electrochemical Characteristics?

2015 ◽  
Vol 33 ◽  
pp. 137-149
Author(s):  
Ayyavu Venkateswari ◽  
S. Kumaran ◽  
C. Nithya
Keyword(s):  
Electron Microscopy ◽  
Milling Time ◽  
Electrode Materials ◽  
Electrochemical Impedance ◽  
Reaction Rates ◽  
High Energy ◽  
Degree Of Crystallinity ◽  
Electrochemical Characteristics ◽  
Transmission Electron ◽  
Milled Powders

Nanostructured Mg2Ni intermetallic compounds were synthesised by high energy ball milling. Effect of milling time on structure and surface morphology of milled powders were studied using X-ray diffraction and scanning electron microscopy. Crystallite size and degree of crystallinity were confirmed using transmission electron microscopy and selective area electron diffraction analysis. In order to understand the effect of milling time on reaction rates, Differential Thermal Analysis is performed. Thermal profiles of 30 h milled powders indicate lower activation energy. Cyclic voltammetry, electrochemical impedance spectroscopy and charge-discharge studies were carried out to understand the electrochemical performance of prepared electrode materials. 30 h milled electrode material delivers maximum discharge capacity with superior capacity retention after 20 cycles at 20 mA g-1.

scholarly journals Biosynthesis of gold nanoparticles-peanut shell composite for catalytic reduction of methyl blue

2020 ◽  
Vol 16 (2) ◽  
pp. 252-257
Author(s):  
Mustaffa Shamsuddin ◽  
Fazleen Kamaludin ◽  
Suhaila Borhamdin
Keyword(s):  
Gold Nanoparticles ◽  
Analytical Data ◽  
High Energy ◽  
Methyl Blue ◽  
Synthesis Process ◽  
Composite Catalyst ◽  
Average Particle ◽  
Peanut Shell ◽  
Shell Composite ◽  
Shell Powder

Gold nanoparticles (AuNPs) has been recognized as an active and effective catalyst for many organic transformations. Currently, there is a growing need to develop AuNPs synthesis process that avoids the use of toxic chemicals or high energy requirement. In this research, the aqueous Phaleria macrocarpa (Mahkota dewa) dried fruit extract was used in the biosynthesis of AuNPs immobilized on peanut shell powder. The peanut shell supported AuNPs was characterized by UV–visible spectroscopy (UV–Vis), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetry analysis (TGA), Nitrogen (N2) adsorption-desorption and atomic absorption spectroscopy (AAS) techniques. The biosynthesized AuNPs was characterized by the appearance of a surface plasmon resonance (SPR) band at 534 nm in the UV–Vis spectrum. The XRD, TEM and TGA analytical data of AuNPs/Peanut shell composite indicated that the AuNPs with face-centred cubic (fcc) crystalline shape, mostly spherical and average particle size of 20.00 ± 4.19 nm were well dispersed on the peanut shell powder support. The FTIR analysis suggested that the C=O and O-H groups in the peanut shell powder have strong affinity to bind and stabilize the AuNPs. The BET surface area of the AuNPs/Peanut shell composite catalyst determined is 35.39 m² g-1 while the BJH pore volume is 0.035 cm3 g-1 with pore diameter of 2.07 nm. AAS elemental analytical data showed the Au loading is 0.03 mmol per gram of catalyst. The catalytic performance of the AuNPs/Peanut shell composite was investigated for the reduction of aqueous methyl blue (MB) at room temperature. The reduction of MB obeyed a pseudo-first-order reaction with the highest rate constant of 0.124 min-1. The supported AuNPs/Peanut shell composite catalyst could be easily recovered and reused for at least three times without significant loss of activity

scholarly journals Exfoliation and Noncovalent Functionalization of Graphene Surface with Poly-N-Vinyl-2-Pyrrolidone by In Situ Polymerization

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1534
Author(s):  
Suguna Perumal ◽  
Raji Atchudan ◽  
Thomas Nesakumar Jebakumar Immanuel Edison ◽  
Jae-Jin Shim ◽  
Yong Rok Lee
Keyword(s):  
Electron Microscopy ◽  
Electrochemical Impedance ◽  
In Situ Polymerization ◽  
Rate Capability ◽  
Vinyl Pyrrolidone ◽  
Graphene Sheets ◽  
One Pot ◽  
Graphene Surface ◽  
Noncovalent Functionalization

Heteroatom functionalization on a graphene surface can endow the physical and structural properties of graphene. Here, a one-step in situ polymerization method was used for the noncovalent functionalization of a graphene surface with poly-N-vinyl-2-pyrrolidone (PNVP) and the exfoliation of graphite into graphene sheets. The obtained graphene/poly-N-vinyl pyrrolidone (GPNVP) composite was thoroughly characterized. The surface morphology of GPNVP was observed using field emission scanning electron microscopy and high-resolution transmission electron microscopy. Raman spectroscopy and X-ray diffraction studies were carried out to check for the exfoliation of graphite into graphene sheets. Thermogravimetric analysis was performed to calculate the amount of PNVP on the graphene surface in the GPNVP composite. The successful formation of the GPNVP composite and functionalization of the graphene surface was confirmed by various studies. The cyclic voltammetry measurement at different scan rates (5–500 mV/s) and electrochemical impedance spectroscopy study of the GPNVP composite were performed in the typical three-electrode system. The GPNVP composite has excellent rate capability with the capacitive property. This study demonstrates the one-pot preparation of exfoliation and functionalization of a graphene surface with the heterocyclic polymer PNVP; the resulting GPNVP composite will be an ideal candidate for various electrochemical applications.

Microwave-assisted one-pot synthesis of anisotropic gold nanoparticles with active high-energy facets for enhanced catalytic and metal enhanced fluorescence activities

CrystEngComm ◽  
2018 ◽  
Vol 20 (30) ◽  
pp. 4297-4304 ◽  
Author(s):  
N. V. S. Praneeth ◽  
Santanu Paria
Keyword(s):  
Gold Nanoparticles ◽  
Au Nanoparticles ◽  
High Energy ◽  
Enhanced Fluorescence ◽  
Rhombic Dodecahedron ◽  
Metal Enhanced Fluorescence ◽  
One Pot ◽  
Microwave Assisted ◽  
Green Route ◽  
Anisotropic Gold Nanoparticles

Rhombic dodecahedron Au nanoparticles synthesized via a microwave assisted green route with high energy {110} facets are highly efficient for catalysis and metal enhanced fluorescence activities.

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