Nano-Co3 O4 was used for electrocatalytic water oxidation due to its promising features of better performance and low cost. An enhanced electrochemical water oxidation performance of the nanoparticles can be achieved by mixing them with other types of highly conductive nano/micro-structured materials. Conductive polymers would be one of the candidates to achieve this goal. Here, we report our recently developed nano-Co3 O4 and polypyrrole composites for enhanced electrochemical water oxidation. We chose polypyrrole as a support of nano-Co3 O4 to obtain highly active sites of nano-Co3 O4 with high conductivity. Morphological and chemical characterization of the prepared materials were performed using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). After immobilizing them individually on fluorine doped tin oxide (FTO) substrate, their electrocatalytic properties toward water oxidation were investigated. The optimum composite materials showed significantly higher electrocatalytic properties compared to that of pure nano-Co3 O4 and polypyrrole. Electrochemical impedance studies indicated that the composite materials possess significantly less electron transfer resistance toward water oxidation reaction compared to that of only polypyrrole or nano-Co3 O4 , while the higher double-layer capacitance and polarization resistance values obtained from fitting of the impedance data represent the faster electrode kinetics in the composite electrocatalyst. Due to the synergetic effect, the optimum nano-Co3 O4 and polypyrrole composites could be represent a novel and promising material for water oxidation.
Keywords: conducting polymers; impedance spectroscopy; nano-Co3O4; polypyrrole; water oxidation.
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