Catalytically Synthesized Prussian Blue by a One-Step Copolymerization of Polydopamine-Polypyrrole for Electrochemical Sensing of Hydrogen Peroxide

Electrochemical sensing of hydrogen peroxide (H2O2) has been considered crucial for biochemical and industrial reasons. Since Prussian Blue (PB) has an excellent catalytic performance of H2O2, many studies have devised various methods to synthesize it. Recently, a method of using the monomer of a certain polymer directly as a reducing agent for Fe3+ to "catalytically" synthesize PB was proposed. However, almost no research has used a couple of monomers to synthesize PB to exploit the strengths of a copolymer, such as polydopamine-polypyrrole (PDA-PPY), that has both stability of PDA and electroconductivity of PPY. In this study, PB was catalytically synthesized with a one-step copolymerization of PDA-PPY for the electrochemical sensing of H2O2. The structure of the PB-PDA-PPY composite was characterized by Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The interfacial property of PB-PDA-PPY/glassy carbon electrode (GCE) was investigated by electrochemical impedance spectroscopy. The electrochemical response of PB-PDA-PPY/GCE towards H2O2 was studied via cyclic voltammetry and amperometry. A particularly wide linear range (5 & mu;M - 1.16 x 104 & mu;M) and a long duration time (2450s) with high linearity (R2 = 0.9996) were noticed with good sensitivity (112 & mu;A mM-1 cm-2) and limit of detection (3.64 & mu;M). Further, besides good reproducibility and stability, the PB-PDA-PPY/GCE showed apparent selectivity to H2O2 than other biological molecules. The one-step copolymerization procedure of PDA-PPY suggested in this study successfully synthesized PB that can be used for H2O2 sensing, which can be extended for other copolymer-based PB composite materials.