Synthesis, characterization and performance of vanadium hexacyanoferrate as electrocatalyst of H2O2

The present work reports for the first time on the synthesis, characterization and performance of vanadium hexacyanoferrate (VHCF) as electrocatalyst of hydrogen peroxide. VHCF was synthesized by mixing V2O5 · nH2O xerogel with ascorbic acid and K4[Fe(CN)6] in double distilled water. X-ray powder diffraction, energy dispersive spectroscopy, scanning electron microscopy, and IR-spectroscopy data suggest the formation of nanocrystalline (mean crystal size∼ 11 nm) compound with a tentative molecular formula K2(VO)3[Fe(CN)6]2. Composite films of VHCF with poly(vinyl alcohol) were developed over a glassy carbon electrode, and then covered with different (neutral, positively or negatively charged) membranes. The effect of each membrane on the working stability of the resultant sensors was evaluated. Cyclic voltammetry experiments showed that composite films exhibit a pair of reversible redox peaks, and a remarkable low potential electrocatalysis on both the reduction and oxidation of hydrogen peroxide. A linear calibration curve over the concentration range 0.01-3.0 mM H2O2 was constructed. Limit of detection (S/N = 3) of 4 μM H2O2 was calculated. The proposed transducer is quite selective to hydrogen peroxide. No response was observed in the presence of 10 mM ascorbic acid.