Application of multi-walled carbon nanotubes/Nafion composite film in electrochemical determination of Pb2+

In this work, insoluble multi-walled carbon nanotubes (MWNTs) was dispersed into ethanol in the presence of 1% Nafion, resulting in a stable and well-distributed MWNTs/Nafion suspension characterized by TEM and particle size analyzer. After evaporation of ethanol, a uniform MWNTs/Nafion composite film-coated glassy carbon electrode (GCE) was prepared and then characterized with SEM. Furthermore, the electrochemical behavior of Pb2+ at the unmodified GCE, Nafion film-modified GCE and MWNTs/Nafion film-modified GCE was investigated. It was found that the reduction peak potential shifts positively and peak current remarkably increases at the MWNTs/Nafion film-modified GCE, suggesting that MWMTs/Nafion film-modified GCE exhibits catalytic ability to electrochemical reduction of Pb2+. Based on this, a sensitive and convenient electrochemical method was proposed for the determination of Pb2+. Finally, the MWMTs/Nafion film-modified GCE was successfully used to detect Pb2+ in a water sample.