Chemical and Plant Mediated Synthesis of La2O3 Nanoparticles and Comparison of their Structural, Antibacterial, Photocatalytic and Optical Properties

The La2O3 nanoparticles have been synthesized successfully with a chemical and biosynthesized method. The optical bandgap energy and of chemically synthesized or biosynthesized (M. oppositifolia and T. portlacaustrum leaf extract) La2O3 nanoparticles was calculated from UV-visible absorption between 5.10, 4.26 and 4.46 eV. The good polycrystalline cubic nature of synthesized La2O3 nanoparticles was evident from the bright circular SAED pattern, consistent with the XRD outcome. It is clear that the non-polar extracts could function as stabilizers for La2O3 nanoparticles through attachment to the counterions. The La2O3 nanoparticles have been used as efficient photocatalyst to degrade acid black 1 dye under sunlight irradiation. Besides, this biocatalyst showed excellent ability to degrade biosynthesized La2O3 nanoparticles (T. portlacaustrum) under visible light irradiation 87%. Synthesis of La2O3 nanoparticles by green chemistry process presented good antibacterial activity against Gram-negative and Gram-positive bacteria.

Wet Chemical Synthesis of CuO-PVA Hybrid Nanofluid Stabilized by Steric Repulsion

CuO-PVA hybrid nanofluid was synthesized within PVA matrix by a simple wet chemical precipitation method. The influence of rate of addition of precursor (NaOH) on the structure, morphology and stability of CuO-PVA hybrid nanofluids were studied. The structure was confirmed by XRD and UV-visible spectroscopy. High resolution transmission microscopy (HRTEM) images revealed the formation of smaller particles for addition of precursor in solid form or rapid addition (RA), whereas slow addition of precursor (SA) resulted in uniform particle size. The selected area electron diffraction (SAED) pattern of sample SA shows rings with small bright spots indicating that the sample is nano crystalline. The SAED pattern of sample RA shows diffuse rings with lesser number of bright spots indicating that it is less crystalline. The stability studies indicate that both the samples were stable for more than one year.

Synthesis and Structural, Optical, Photoluminescence and Electronic Structure Studies of SrAl2O4 Phosphor

In this work, pure SrAl2O4 phosphor is synthesized using precipitation method annealed at 1000 ºC and characterized by XRD, FTIR, UV-visible, Raman, SEM, EDX, TEM, SAED and photoluminescence spectroscopy. The XRD pattern reveals the unit cell structure of SrAl2O4 as monoclinic. The SEM and TEM images show a non-uniform shape with agglomeration, and its size varies from 10 to 80 nm. The SAED pattern confirms polycrystalline and single crystal in the different selected area with different magnification. Photoluminescence emission shows a peak at 467 nm (blue) when excited at 272 nm wavelength. The electronic structure calculation with the density functional theory (DFT) shows a band gap of 4.4 eV, which is nearly equal to 4.46 eV obtained from the experiment optical absorption spectrum. The findings would be beneficial for furthermore investigations on doping in the pure SrAl2O4 phosphor to enhance its high luminescent intensity and long-lasting for a future technological purpose.

Preparation and characterizations of Graphene oxide and Graphene NPs

An eco-friendly and inexpensive process of reduction of Graphene oxide using extract of Amla juices is here in reported. The objective is to reduce Graphene oxide to Graphene nanoparticles. The crystallite size of nanoparticles Graphene was confirmed by XRD analysis. FTIR spectral analysis revealed the reduction of Graphene oxide using extract of Amla juices. The morphology of the synthesized Graphene was examined by TEM analysis and SAED pattern. From Graphene oxide which was prepared by Hummer method is reduced to Graphene by using Amla juices as reducing agent. To synthesize Graphene nanoparticles using a cost effective green method and to analyze how Graphene improves a device with respect to cost, production and efficiency. The toxicity of the Graphene nanoparticles will be reduced through the green method.

Synthesis of a Polyaniline Nanoparticle Using a Solution Plasma Process with an Ar Gas Bubble Channel

This work researched polymerization of liquid aniline monomer by solution plasma with a gas bubble channel and investigated characteristics of solution plasma and polyaniline (PANI). The injected gas bubble channel in the proposed solution plasma process (SPP) played a significant role in producing a stable discharge in liquid aniline monomer at a low voltage and furthermore enhancing the contact surface area between liquid aniline monomer and plasma, thereby achieving polymerization on the boundary of the liquid aniline monomer and plasma. Solution plasma properties were analyzed with voltage–current, optical emission spectroscopy, and high-speed camera. Conductivity, percentage yield, and firing voltage of PANI nanoparticle dispersed solution were measured. To investigate the characteristics of synthesized PANI nanoparticles, field emission scanning electron microscopy, dynamic light scattering, transmission electron microscopy, selective area electron diffraction (SAED) pattern, Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography, 1H-nuclear magnetic resonance (1H-NMR), and X-ray photo spectroscopy (XPS) were examined. The FTIR, 1H-NMR, and XPS analysis showed the PANI characteristic peaks with evidence that some quinoid and benzene rings were broken by the solution plasma process with a gas bubble channel. The results indicate that PANI nanoparticles have a spherical shape with a size between 25 and 35 nm. The SAED pattern shows the amorphous pattern.

Efficient NO Photodegradation of Hydrothermally Synthesized TiO2 Nanotubes under Visible Light

In this study, TiO2 nanotubes (TNTs) were synthesized via a hydrothermal process and characterized by high-resolution transmission electron microscopy (HR-TEM) images, selected area electron diffraction (SAED) pattern, and photoluminescence (PL) analysis. The NO removal photocatalytic activity of the hydrothermally synthesizedTNTs was surveyed systematically. The hydrothermally synthesizedTNTs have shown an efficient NO photodegradation which is approximately 4 times higher than that of P25 and an excellent photostability under visible light after 5 cycles. Furthermore, reactive radicals mainly involved in the photocatalytic reaction were identified by electron spin resonance (ESR) study, leading to a better understanding of the photocatalytic mechanism of the hydrothermally synthesized TNTs.

SYNTHESIS AND CHARACTERIZATION OF SILVER NANOPARTICLES FROM MARINE BROWN SEAWEED AND ITS ANTIFUNGAL EFFICIENCY AGAINST CLINICAL FUNGAL PATHOGENS

Objectives: The aim of this study is to synthesize silver nanoparticles using the algal extract of Padina tetrastromatica and evaluate its antifungal activity against pathogenic fungus isolated from clinical samples.Results: Formation of brown color at 15 minutes indicates the production of silver nanoparticles by the extract of brown algae P. tetrastromatica. Surface plasmon resonance band was centered at 440 nm which was observed by UV-vis spectrophotometer. SEM image revealed spherical and cubical nanoparticles with high agglomeration, and energy-dispersive X-ray illustrates elemental components of silver formed at 3 keV. TEM shows spherical, truncated, and ellipsoidal nanoparticles and also it evidences the algae compounds that are capped with nanoparticles. SAED pattern proved four diffraction face-centered cubic rings at (111), (200), (220), and (311) which indicates the crystalline nature of nanoparticles. Silver nanoparticles show high inhibition activity against Fusarium sp, Aspergillus niger, Candida albicans, Aspergillus fumigatus, and Aspergillus flavus at different concentrations. P. tetrastromatica-mediated synthesis of silver nanoparticles shows rapid and eco-friendly silver ion reduction process.Methods: Dried algal biomass was used to prepare the pure algal extract and added with 1 mM AgNO , and the color change was noted and recorded by ultraviolet (UV)-vis spectrophotometer. The morphological characteristics were analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Crystalline structure was analyzed by SAED pattern. Antifungal activity was performed by agar well diffusion method against various pathogenic fungi.Conclusion: Therefore, this present study elucidates that algae-mediated synthesized silver nanoparticles have antifungal activity against pathogenic fungi, so it can be developed as a novel medicine for human welfare in biomedical applications in the near future.Keywords: Padina tetrastromatica, Silver nanoparticles, Transmission electron microscopy, Antifungal activity, Green synthesis.

Ag-embedded MnO nanorod: facile synthesis and oxygen reduction

TEM images of as-prepared nanocomposites under a Ag/Mn molar ratio of 1/200. Inset in (b): HR-TEM image taken from image (b); inset in (c): SAED pattern taken from one individual nanorod.

Preparation of water-dispersible graphene using N-methylmorpholine N-oxide monohydrate and its application for the preparation of nanocomposites using PEDOT

SEM and TEM images (inset: selective area electron diffraction (SAED) pattern) of mono-layered water dispersible graphene (GPN) sheet by treatment ofN-methylmorpholineN-oxide monohydrate (NMMOm).