Ag Ion Irradiation of Multi-Walled Carbon Nanotubes Modified ITO Induces Electrocatalytic Effects

Energetic ion irradiation has been used as a tool to improve the electrocatalytic activity  of multi-walled carbon nano tubes (MWCNTs) modified indium tin oxide (ITO). A thin film of MWCNTs was irradiated with Ag  ions having energy of 120 MeV with fluences of 1x10¹², 3x10¹² and 1x10¹³ ions/cm², using a palleteron accelerator. The structural differences between un-irradiated and irradiated thin films were characterized by SEM observation and energy dispersive x-ray analysis. The change in MWCNTs due to ion beam irradiation was determined by Raman spectroscopy. The effect of irradiation on the electrocatalytic activity was examined by voltammetric measurements on epinephrine and it was found that irradiation improved peak current response. The anodic peak current for epinephrine increased by ~10 times in the pH range 2.0 -10.0 over that for the original MWCNTs and the peak potential shifted to less positive values. The detection limit (3<sigma>/slope) and sensitivity for epinephrine for the pristine material were found to be 100 nM and 0.1086 <mu>A/<mu>M as compared to 2 nM and 0.998 <mu>A/<mu>M for the Ag ion beam irradiated MWCNT.