Shaneel Chandra^{1, 2,}, Wycliff Tupiti², Sevlin Singh², Zafiar Naaz², Pritika K. Kishor², Archana Goundar², Malina Fakraufon², Surendra Prasad²

This paper reports an undergraduate experiment based on analytical chemistry, electrochemistry and materials science of carbon microelectrodes. The modification of the electroactive surface of the carbon microelectrode was done using gold nanoparticles electrodeposited from gold solution. To determine the changes on the surface, the electrode was subjected to simple optical microscopy. Next, the electrode was characterized using fast-scan cyclic voltammetry of two known electrochemical redox markers: hexaamineruthenium(III) chloride and potassium hexacyanoferrate (III), i.e. potassium ferricyanide. The redox behavior of both markers demonstrated the change in electrode surface. After modification, the ferricyanide reduction peaks were observed to increase significantly, as a consequence of accelerated electron transfer. Furthermore, changes in wave slope and half-wave potentials (E_½) of the redox waves also confirmed an altered electrode surface that students can logically trace back to the modification. The electrode tip dimension was also determined using a modified form of the Cottrell equation, confirming the tip size to be 2.0 µm. The discussion of these results enables an understanding of electrochemistry, analytical chemistry and materials chemistry, and presents an excellent opportunity to apply these in an undergraduate setting.

upper-division undergraduate, laboratory instruction, physical chemistry, hands-on learning, electrochemistry, materials science, surface science