One-pot electrochemical preparation of copper species immobilized poly(o-aminophenol)/MWCNT composite with excellent electrocatalytic activity for use as an H2O2 sensor

Abstract

Redox activity of copper species immobilized poly(o-aminophenol)/multi-walled carbon nanotube (Cu@MWCNT-POAP) composite is reported for direct electrocatalysis towards detection of H₂O₂. The Cu@MWCNT-POAP composite was prepared by a single step in situ electrochemical method. The as-prepared Cu@MWCNT-POAP composites were characterized by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, and electrochemical impedance spectroscopy. Cyclic voltammetry (CV) studies highlighted the good redox behavior of the Cu@MWCNT-POAP composite resulting from direct electron transfer behavior of the copper redox couple (Cu²⁺/Cu⁺). The Cu@MWCNT-POAP composite displayed superior electrocatalytic activity and high performance towards detection of H₂O₂ because of its large surface area and homogenous immobilization of Cu species on the MWCNT-POAP composite. The analytical sensitivity and detection limit of the sensor were 831 μA mM⁻¹ cm⁻² and 30 nM, respectively. In addition, bio-catalytic activity of the sensor was evaluated using the Michaelis–Menten constant. The Cu@MWCNT-POAP composite showed excellent stability and reproducibility, and good recoveries for determination of H₂O₂ in milk, bleach cream, and contact lens solutions.