Iron(III) oxide adsorbed multiwalled carbon nanotube modified glassy carbon electrode as a precursor for enhanced Prussian blue formation and selective hydrogen peroxide sensing

Abstract

Prussian blue (PB), an inorganic iron-hexacyanoferrate polymer, is a potential redox system. In general, it can be prepared on any conducting substrate by electrochemical deposition technique in which a working electrode is potential cycled with millimolar quantities of a mixture FeCl3 and [Fe(CN)6]3− in an alkaline metal ion containing acid solution (pH<3). Here in we report preparation of a new hybrid PB by a template assisted preparation method, where rather to taking any mixture, the [Fe(CN)6]3− is subjected to the electrochemical potential cycling technique with a Iron(III) adsorbed multiwalled carbon nanotube modified glassy carbon electrode (GCE/MWCNT–Fe2O3), as a template, in pH 2 KCl–HCl. The PB electrode thus designated as GCE/MWCNT–Fe2O3@PB showed well-defined redox peaks at apparent standard electrode potentials, 190±5 and 850±5mV vs Ag/AgCl and synergistic effect of PB, MWCNT and Fe2O3 systems. As prepared MWCNT–Fe2O3@PB was characterized by various physico-chemical techniques such as Scanning electron microscopy, Energy dispersive X-ray analysis, X-ray photoelectron spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy and Raman spectroscopy. Presence of trace amount of the precursor, Fe2O3 within the inner core of the hybrid PB system was evident from the characterization results. In further, it was found that one of the metallic impurities, iron in the MWCNT has influenced the PB formation. The new hybrid PB electrode exhibited 17 times higher reduction current value over the conventionally prepared GCE/PB for the H2O2 electrocatalysis. Applicability of the electrode to sensing of H2O2 in real sample such as milk, cream bleach and clinical solution was successfully demonstrated.