Self-assembly of [NbWO6]- nanosheets and cobalt porphyrin with an enhanced electrocatalytic activity

A layered nanocomposite CoTMPyP/NbWO6 was fabricated by exfoliation/restacking method. The structure and morphology of LiNbWO6, HNbWO6 and CoTMPyP/NbWO6 were characterized by XRD, SEM, TEM, EDS, UV-Vis and IR. It indicated that the CoTMPyP molecules were arranged about 67 degrees between the layers of [NbWO6](-). Moreover, the Zeta potential of [NbWO6](-) colloidal dispersion is -45.7 mV, indicating that the colloidal suspension exfoliated by TBAOH solution is stable. Meanwhile, the cyclic voltammetry (CV) and the differential pulse voltammetry (DPV) measurements were used to explore the electrochemical properties of CoTMPyP/NbWO6 nanocomposite modified glass carbon electrode (GCE). The modified GCE exhibited excellent electrocatalytic activity toward ascorbic acid (AA) oxidation and the oxidation reaction was proved to be a diffusion-controlled process. DPV measurements demonstrated that the CoTMPyP/NbWO6 modified electrode detects AA linearly over a concentration range of 7.49 x 10(-5 )to 2.89 x 10(-3) mol L-1 with a detection limit of 2.5 x 10(-5) mol L-1 at a signal-to-noise ratio of 3.0.