Abstract

Nickel oxide (NiOx) and polyaniline (PAni) were electrocodeposited from NiSO4 and aniline through cyclic voltammetric scans to afford PAni–NiOx composite film at controlled pH environment. The electrochemical activities of the film were investigated by cyclic voltammetry in 0.1 M NaOH and 0.1 M H2SO4, respectively. Typical redox couples of PAni in 0.1 M H2SO4 appeared at approximately 0.2 and 0.4 V vs. saturated calomel electrode (SCE); Ni(II)/Ni(III) redox couple was observed at approximately 0.4 V vs. SCE in 0.1 M NaOH. The morphologies and elemental components of the films were inspected by scanning electron microscopy and energy dispersive X-ray diffraction. The stability of nickel oxide in the films was found to be enhanced against acidic environments. Electrochemical catalytic behavior of NiOx within the composite film was conserved and demonstrated by catalytic oxidation of methanol and ethanol.