Electrochemical Sensor Based on Prussian Blue Electrochemically Deposited at ZrO₂ Doped Carbon Nanotubes Glassy Carbon Modified Electrode

In this work, a new hydrogen peroxide (H₂O₂) electrochemical sensor was fabricated. Prussian blue (PB) was electrodeposited on a glassy carbon (GC) electrode modified with zirconia doped functionalized carbon nanotubes (ZrO₂-fCNTs), (PB/ZrO₂-fCNTs/GC). The morphology and structure of the nanostructured system were characterized by scanning and transmission electron microscopy (TEM), atomic force microscopy (AFM), specific surface area, X-ray diffraction (XRD), thermogravimetric analysis (TGA), Raman and Fourier transform infrared (FTIR) spectroscopy. The electrochemical properties were studied by cyclic voltammetry (CV) and chronoamperometry (CA). Zirconia nanocrystallites (6.6 ± 1.8 nm) with cubic crystal structure were directly synthesized on the fCNTs walls, obtaining a well dispersed distribution with a high surface area. The experimental results indicate that the ZrO₂-fCNTs nanostructured system exhibits good electrochemical properties and could be tunable by enhancing the modification conditions and method of synthesis. The fabricated sensor could be used to efficiently detect H₂O₂, presenting a good linear relationship between the H₂O₂ concentration and the peak current, with quantification limit (LQ) of the 10.91 μmol·L^-1 and detection limit (LD) of 3.5913 μmol·L^-1.