Au-modified organic/inorganic MWCNT/Cu/PANI hybrid nanocomposite electrode for electrochemical determination of nitrate ions.

A new electrochemical sensor is reported for the based on the application of noble bimetal nanoparticles (gold and copper) to polymeric-carbon-modifiers for the reduction of nitrate. This sensor was designed for nitrate ion measurement at the surface of pencil graphite electrode modified by a nanocomposite. The modification was the electrosynthesis of gold nanoparticles on the MWCNT/copper-polyaniline (Cu-PANI) nanocomposite. Physicochemical properties of the synthesized hybrid nanocomposites and their surface performance efficiency are characterized using microscopic, spectroscopic, and electrochemical techniques. At optimized pH, the nitrate peak current (at working potential of 1084 mV versus Ag/AgCl reference electrode) was linear in the concentration range 0.8-30.0 µM with a detection limit of 0.09 µM using differential pulse voltammetry. Modified sensor was successfully implemented to quantify nitrate ions in wastewater resulting from the production line for industrial barium chromate and an example of aqueduct water with appropriate recovery levels. • Aniline was polymerized in phosphoric acid solution using peroxydisulfate as an initiator. • MWCNT@CuNPs@PANNSs@AuNPs nanocomposite on PGE electrode was revealed specific recognition for NO3-. • The electrochemical sensor displayed high selectivity and sensitivity for the detection of NO3-.

Novel room temperature synthesis of ZnO nanosheets, characterization and potentials in light harvesting applications and electrochemical devices.

Zinc oxide nanosheets (ZnONSs) were successfully synthesized using Zn(NO3)2·4H2O as the starting reagent in ammonia atmosphere at room temperature by a novel gas-solution precipitation method. XRD and EDS patterns indicated that pure ZnONSs were produced only in 15min reaction time. Besides, investigating the optical properties of the as-prepared ZnO nanosheets using UV-Vis diffused reflectance spectroscopy (DRS) exhibited their semiconducting property by revealing one optical band gap in 3.3eV. Moreover, rhodamine B and methylene blue degradation were used as a probe reaction to test the as-synthesized ZnONSs photoactivity. Furthermore, a possible reaction mechanism for ZnONSs formation was discussed. On the other hand, operation of ZnONSs in Dye-sensitized solar cell (DSSC) was investigated by current density-voltage (Jsc-Voc) curve. Finally, a pencil graphite electrode was decorated using ZnONSs and pure MWCNT to provide an electrochemical device for Pb(+2) ions sensing. This modified electrode showed agreeable responses to trace amounts of Pb(+2) in NaOAC/HOAC buffer solutions. The limit of detection was found to be 0.112nmolL(-1) for Pb(+2).