Devaraj Manoj

Au–ZnO bullet-like heterodimer nanoparticles: synthesis and use for enhanced nonenzymatic electrochemical determination of glucose

In this work, the gold nanoseed mediated growth of bullet-like gold–zinc oxide (Au–ZnO) heterodimer nanoparticles has been reported. A formation pathway for the bullet-like morphology has been proposed. The heterojunction effect of the Au–ZnO nanoparticles was studied using UV-vis spectroscopy, X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HRTEM) and electrochemical impedance spectroscopy (EIS). The bullet-like Au–ZnO heterodimer nanoparticles were effectively employed as a sensor for the nonenzymatic determination of glucose (GLU) in a Au–ZnO/MWCNTs/GC modified electrode. This showed good sensitivity and a wide linear range of 19–291 μM with a sensitivity of 0.0447 μA μM−1 and a limit of detection of 0.19 μM. The resulting sensor displayed excellent repeatability and long-term stability.

Electrostatic fabrication of oleylamine capped nickel oxide nanoparticles anchored multiwall carbon nanotube nanocomposite: A robust electrochemical determination of riboflavin at nanomolar levels

A simple and strong electrostatic adsorption of oleylamine (OLA) capped nickel oxide (NiO) nanoparticles (oleylamine–amine group) onto the acid functionalized multiwalled carbon nanotubes (MWCNTs) (–COOH group) through coulombic interaction, leads to the construction of OLA–NiO/MWCNTs nanocomposite. The optimum loading of OLA–NiO nanoparticles on to the acid functionalized MWCNTs is investigated by Fourier transform infrared spectroscopy. Moreover, the optimum amount of loading and stability of the modified electrodes were studied by using linear sweep voltammetry and conductivity of optimum loadings are also studied by electrochemical impedance spectroscopy. OLA–NiO/MWCNTs nanocomposite was fabricated on glassy carbon electrode for the electrochemical determination of riboflavin (RF) at nanomolar levels. The results show a dynamic linear range of 0.009–55.9 μM with excellent sensitivity of 0.489 μA μM−1 and the limit of detection was found to be 1 nM (S/N = 3). The developed OLA–NiO/MWCNTs composite decorated GC exhibited good sensitivity, stability, and reproducibility for the determination of RF in differential pulse voltammetry. The OLA–NiO/MWCNTs/GC modified electrode was applied for the determination of RF in pharmaceutical formulation tablet and syrup samples.

Synthesis, H2PO4− and Pd2+ ion sensing and gold nanoparticle encapsulation of ferrocenyldendrimers by a green chemistry approach

A green chemistry approach for the synthesis of three novel ferrocenyldendrimers containing a triazolyl ferrocenyl group at the periphery under microwave conditions using an ionic liquid (IL) mediated click reaction is described. The application of such ferrocenyldendrimers as sensors for H2PO4− and Pd2+ is also discussed. The ferrocenyldendrimers which are used for the synthesis of Au nanoparticles were characterized using UV-Vis, spectroscopy and high resolution transmission electron microscopy (HRTEM). From the HRTEM images it is shown that dendrimer 1 stabilizes the gold nanoparticle, whereas dendrimers 2 and 3 encapsulate the gold nanoparticle.

Structural and optical properties of 2D CuO nanoleaves

In this paper, 2D CuO nanoleaves have been synthesized via a simple alcoholic reduction method. The asprepared CuO nanoleaves appear to be leaf like structure with an average size of 400 nm in length and 150 nm in width. The optical band-gap energy of the CuO nanoleaves was calculated from the absorbance spectrum to be 1.7eV.