Study of multi-wall carbon nanotubes self-assembled electrode and its application to the determination of carbon monoxide

A novel electrochemical sensor based on multi-wall carbon nanotubes (MWCNTs) has been developed for the determination of carbon monoxide (CO). The catalytic activation of multi-wall carbon nanotubes microelectrode (MWCNTME) with Pt micro-disk as substrate was investigated in different supporting electrolyte solutions by cyclic voltammetry and constant potential transient method. The result shows that MWCNTME exhibited strong catalytic effect toward the electrochemical oxidation of carbon monoxide in 0.5 mol l−1 HClO4. As compared with the bare Pt disk electrode, MWCNTME can greatly decrease the overpotential and obviously increase the current of CO oxidation. The current–time curve recorded under conditions of constant potential and various CO concentrations suggests that current response depend linearly on CO concentration. A linear equation I (μA)=0.00624c (μg ml−1)+0.2299 with a correlation coefficient of 0.9957 was obtained over the concentration range 0.72–52 μg ml−1 at potential +700 mV relative to Ag/AgCl reference electrode. The detection limit was 0.60 μg ml−1 and the relative standard deviation was 4.8% (n=5) at room temperature.