The electrochemical effect of acid functionalisation of carbon nanotubes to be used in sensors development

► Multi-walled carbon nanotubes as catalyst materials. ► Outer and Inner sphere electrochemical reactions studies. ► Dopamine and Fe(CN)63-/4- present a good electrochemical systems to show electrochemical features of the carbon nanotubes. ► Acid pre-treatment promotes the enhancement of electrochemical response.