Electrochemical behavior of amino-modified multi-walled carbon nanotubes coordinated with cobalt porphyrin for the oxidation of nitric oxide

Cobalt (II) tetrakis (4-sulfonatophenyl) porphyrin (CoTPPS) was axially coordinated with amino-modified multi-walled carbon nanotubes (MWCNT) to form a MWCNT-CoTPPS hybrid. The hybrid was drop cast on the glassy carbon electrode (GCE) to obtain MWCNT-CoTPPS/GCE. The structure of the MWCNT-CoTPPS hybrid was characterized by field-emission transmission electron microscope. X-ray photoelectron spectroscopy was also conducted to characterize the MWCNT-CoTPPS hybrid. Cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry were used to evaluate the electrocatalytic activity of MWCNT-CoTPPS/GCE for the oxidation of nitric oxide (NO). The effects of potential scan rate, temperature and NaNO2 concentration on the electrochemical oxidation of NO at the MWCNT-CoTPPS/GCE were studied in detail. The obtained MWCNT-CoTPPS/GCE demonstrated a potential application for detecting NO in aqueous solution.