Electro-catalytic oxidation of methane at multi-walled carbon nanotubes-Nafion/nickel hydroxide modified nickel electrode

A novel chemical modified nickel (Ni) electrode based on multi-walled carbon nanotubes (MWCNTs), Nafion film and nickel hydroxide has been successfully fabricated for methane (CH4) detection at ambient conditions. The morphology of the MWCNTs–Nafion/Ni(OH)2 film was characterized by transmission electron microscopy and the electrochemical properties of the Ni modified electrode were studied by cyclic voltammetry. The MWCNTs–Nafion/Ni(OH)2–Ni electrode showed good catalytic effect on the oxidation of CH4 in 1.0 M NaOH. In addition, the modified electrode was free from nitrogen and oxygen interferences. When differential pulse voltammetry was applied to the MWCNTs–Nafion/Ni(OH)2–Ni electrode, a good linear relationship between the oxidation peak current (i) and CH4 concentration (Cmethane) was obtained: i = 1.841Cmethane + 46.25, where i is in μA and Cmethane is in 0.0–16.0% (v/v). The relative standard deviation for detection of 3.0% (v/v) CH4 was 1.80% (n = 5). The proposed Ni modified electrode is anticipated to provide a promising technique to detect CH4 at ambient conditions.