Synthesis of polypyrrole coated copper nanowire and its application as hydrogen peroxide sensor

Abstract

Polypyrrole coated copper nanowire was synthesized by a metal-organic complex route in one-pot manner. The as-synthesized copper nanowires were single crystalline which grew along the {110} direction with {111} facets exposed on the surface. A layer of polypyrrole coating with a thickness of 5-6 nm could also be observed on the surface of the nanowires, as confirmed by HRTEM. Based on the real-time monitoring of the spectral and electrochemical potential change for the synthetic process, it was believed that a synergistic crystal growth and polymerization effect eventually led to the formation of the polypyrrole coated copper nanowire. The ligand-to-metal charge transfer (LMCT) excitation between pyrrole and the cupric central ion, along with the capping effect of polypyrrole would attribute significantly during this formation process. However, the electrochemical properties of the copper nanowires did not alter notably with the presence of polypyrrole coating, and they also exhibited sufficient electrocatalytic property towards hydrogen peroxide reduction in phosphate buffer solution. A potentiometric sensor based on the copper nanowire modified graphite electrode was therefore fabricated to investigate the sensory ability of the copper nanowires to hydrogen peroxide. The modified electrode exhibited high selectivity and sensitivity of 180.65 mV/mM to hydrogen peroxide, unambiguously revealing the excellent sensory properties of the as-synthesized copper nanowire to hydrogen peroxide. The copper nanowire also exhibited substantially enhanced anti-corrosion properties compared to the uncoated sample, which unraveled the unprecedented application potential for the copper nanowires in sensors, catalysts, and nanoelectronics, as a result of its excellent electrochemical activity and environmental stability.