A highly sensitive and selective nanosensing probe for mercury ion is reported. Herein highly luminescent cysteine(cys) functionalized Graphene quantum dots(GQDs) were fabricated through facile one-step pyrolysis method by using ethylene glycol and cysteine. The coating of cysteine not only increases quantum yield to 41% but also enhances selective detection of ppb level of mercury ion in the waste water. The fluorescence intensity of Cys-GQDs was sequentially quenched by different concentrations of mercury ion via forming non-luminescent complexes of Cys-GQDs-Hg(II). HR-TEM study clearly shows a monodisperse Cys-GQDs of sizes 2-5 nm with a spherical shape. Raman spectra of Cys-GQDs display the D and G bands at 1350 cm−1 and 1580 cm−1 respectively. Optimum pH is 8 for mercury detection. The minimum limit for accurate detection of mercury is 0.64 ppb
In the present work Polypyrrole nanoparticles are synthesized by oxidative polymerization method in the presence of aqueous nitric acid(HNO3) as solventandferric chloride (FeCl3) as oxidizing agent. During polymerization process the solvent and oxidizing agents played a crucial role in modifying the nanostructures of polypyrrole (PPy). Scanning electron microscopy (SEM) revealed theuniform globule morphology and narrow size distribution of produced PPy particles in acid medium. Combined effect of solvent and oxidant are advantageous for the production of PPy nanoparticles (PPyNPs) with a yield of 90%.Four point probe method and strong UV-Visible band confirmhigh electrical conductivity of PPy due to a large Π-conjugation in the polymer structure. The nature and composition of PPyNPs were confirmed by X-ray diffraction (XRD) spectrometer and Fourier transform infrared spectroscopy (FTIR). Electrochemical properties were confirmed by cyclic voltammetry (CV) and galavanostatic charge discharge (GCD) spectrum.CV and GCD spectra illustrate the excellent electrochemical properties of PPyNPs which show higher specific capacitance of 398F g−1 at 100mAg−1 current density.It has wide applications in electronic and electrochromic devices, sensors, membrane separation,corrosion protection, chromatographic stationary phase, rechargeable batteries, drug delivery,supercapacitors,light-weight batteries and microwave shielding etc.
Cerium oxide synthesis (CeO2) nanoparticles were studied using a new and simple, eco-friendly process. The cerium oxide nanoparticles are synthesized with precursors of ammonium cerium nitrate and sodium hydroxide. Their chemical and physical properties are characterized by energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transforming infrared spectroscopy (FTIR), and UV-Vis spectrophotometer scanning electron microscopy (SEM), high-resolution electron transmission microscopy (HRTEM). XRD analysis indicated the cubic structure of the nanoparticles containing cerium oxide. The standard particle size of CeO2 was determined at 30 nm using HR-TEM and XRD. SEM determine the surface morphology of biosynthesized cerium oxide nanoparticles. A Ce-O stretching mode was defined by the strong peaks in the FTIR range, and the peak of UV-Vis range absorbance revealed the 3.26 eV band energy difference.
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