Journal of Materials Science, Vol.50, No.19, 6469-6476, 2015
A laminar nanocomposite constructed by self-assembly of exfoliated alpha-ZrP nanosheets and manganese porphyrin for use in the electrocatalytic oxidation of nitrite
Laminar nanocomposite of alpha-ZrP/MnTMPyP, [5, 10, 15, 20-tetrakis (N-methylpyridinium-4-yl) porphyrinato manganese (III)], was obtained through the self-assembly of alpha-ZrP nanosheets and manganese porphyrin molecules, namely the exfoliation/restacking route. The final products were characterized by several analytic techniques such as XRD, IR, UV-Vis, and SEM. Meanwhile, the surface charge change of layered zirconium phosphate during the restacking process was monitored by a Zetasizer Nano instrument. The zeta potential value of alpha-ZrP colloidal dispersion is -40.1 mV, indicating that the colloidal dispersion was stable and well dispersed. The cyclic voltammetry measurements of alpha-ZrP/MnTMPyP film-modified glass carbon electrode displayed a pair of well-defined oxidation/reduction peaks with redox potentials at -0.256 and -0.197 V with an increase in the peak current compared to MnTMPyP aqueous solution. Furthermore, alpha-ZrP/MnTMPyP hybrid thin film exhibited excellent electrocatalytic activities toward oxidation of nitrite. The oxidation peak current increased linearly with the square root of scan rate, suggesting that the electrocatalytic process was controlled by nitrite diffusion. Finally, a detection limit of 5.3 x 10(-5) M was estimated at a signal-to-noise ratio of 3.0 with a concentration range of 1.5 x 10(-4) to 4.76 x 10(-3) M.