In Situ Prussian Blue-Electrocatalyst Formation on Intrinsic Iron-Containing Pristine-MWCNT as a Template and Its EQCM and SECM Interrogations and Batch Injection Analysis of Hydrogen Peroxide

Herein, we report in-situ electrochemical derivatization of the intrinsic iron species in a pristine-multiwalled carbon nanotube (MWCNT) as Prussian blue (PB) modified MWCNT hybrid (MWCNT@PB) using a dilute solution of ferricyanide as a derivatization agent in pH 2 HCl-KCl solution. The PB hybrid system showed a defined redox peak at an apparent standard electrode potential, E o ’ = 0.18 V vs Ag/AgCl with an excess surface value, 1.71 × 10 −10 mol cm −2 . A discreet EQCM study on the electrochemical preparation of MWCNT@PB using MWCNT and ferricyanide precursors reveal the specific stripping of iron species and uptake of iron species, potassium and ferricyanide ions upon the electrochemical preparation condition. In-situ imaging of MWCNT@PB was carried out using SECM with ferricyanide as a redox mediator under a feedback-current mode. It has been identified that a mixed-potential based electrochemical reaction involving oxidative stripping of iron to iron ion species (step-1) coupled with reduction of ferricyanide to ferrocyanide (step-2) followed by a chemical interaction between the iron ion and ferricyanide (step-3) have occurred for the overall formation of MWCNT@PB hybrid. Electrocatalytic and electroanalytical performance of the MWCNT@PB hybrid towards H 2 O 2 reduction and sensing were demonstrated by performing cyclic voltammetric, amperometric i-t and batch injection analysis. In-situ derivatization of intrinsic iron in pristine MWCNT to Prussian Blue (PB) is described. Intrinsic iron (∼2 wt.%) containing MWCNT was used as a template for PB with Fe(CN) 6 3− ion EQCM and SECM techniques were used for the mechanistic and visualization of the PB formation MWCNT@PB hybrid was used as an electrocatalyst for H 2 O 2 reduction reaction MWCNT@PB was used as a home-made detector for Batch Injection Analysis of H 2 O 2