Electrochemistry and XPS of 2,7-dinitro-9-fluorenone immobilized on multi-walled carbon nanotubes

Abstract

We report that glassy carbon electrodes (GCE) modified with multi-walled carbon nanotubes (MWCNTs) can be derivatized with 2,7-dinitro-9-fluorenone (2,7-NFN). The derivatization procedure involves simple immersion of the MWCNT-modified electrode in a solution containing 2, 7-NFN. SEM images indicate that the MWCNTs form a twisted, three-dimensional array that remains attached to the GCE surface. Both electrochemical and spectroscopic measurements (XPS) indicate that 2,7-NFN is immobilized on the electrode, most probably by being trapped within the pockets of the mentioned three-dimensional array. The electrode with the immobilized 2,7-NFN is sufficiently stable to resist washing but allows both its manipulation and reduction to form the hydroxylamine derivative. This derivative can be oxidized to form a nitroso compound. Both the nitroso and hydroxyl amine derivatives are also trapped within the MWCNT surface pockets. Furthermore, depending on the selected working potential, the nature of the encapsulated compound, i.e., nitro, nitroso, or hydroxylamine derivative and mixtures thereof, can be selected. All these redox pathways were verified by cyclic voltammetry and XPS.