Cobalt ferrite nanoparticles as a source of intrinsic metals for simultaneous electrosynthesis of Prussian blue and cobalt hexacyanoferrate

Abstract

A novel method is proposed for the simultaneous electrochemical formation of Prussian blue (PB) and cobalt hexacyanoferrate (CoHCF) on the surface of edge-plane pyrolytic graphite electrodes (EPPGE) modified by CoFe2O4/Chit/PTCA nanoparticle (NP) (where CoFe2O4 = cobalt ferrite, Chit = chitosan, and PTCA = Perylene-3,4,9,10-tetracarboxylic acid). The PB and CoHCF films are formed from the NP intrinsic metals (Fe3+ and Co2+) in the presence of ferrocyanide ([FeII(CN)6]4−) dissolved in a Britton-Robinson (BR) buffer at pH 1.60. The extent of the film formation is determined by the amount of the PTCA immobilised on the CoFe2O4/Chit NP surface and is influenced by the components of the BR buffer medium. Larger amounts of immobilised PTCA enhance electrosynthesis and generate modified electrodes in situ with excellent electrochemical properties. Optimized electrodes increased electroactive area approximately 420% compared to bare EPPGE. We believe that the combination of NP intrinsic metals, PTCA immobilisation, use of [FeII(CN)6]4− and BR buffer components provides a new electrochemical structure for simultaneous production of PB and CoHCF films. The quality of the electrodes generated in situ by the present method is evidenced by their increased sensitivity and enhanced active surface area relative to bare EPPGE, which indicates its potential for future application in electrochemical sensors.