Direct electrochemistry and electrocatalysis of myoglobin using an ionic liquid-modified carbon paste electrode coated with Co₃O₄ nanorods and gold nanoparticles

A nanohybrid biomaterial was fabricated by mixing Co₃O₄ nanorods, gold nanoparticles (Au-NPs) and myoglobin (Mb), and depositing it on the surface of a carbon paste electrode containing the ionic liquid N-hexylpyridinium hexafluorophosphate as the binder. UV–vis and FT-IR revealed the Mb in the composite film to have remained in its native structure. A pair of well-defined redox peaks appears in cyclic voltammograms and indicates direct electron transfer from the Mb to the underlying electrode. The results are attributed to the favorable orientation of Mb in the composite film, to the synergistic effects of Co₃O₄ nanorods and Au-NPs. The modified electrode shows excellent electrocatalytic ability towards the reduction of substrates such as trichloroacetic acid and nitrite, and displays good stability and reproducibility. (author)