Electrochemical Detection of H2O2 on Graphene Nanoribbons/Cobalt Oxide Nanorods-Modified Electrode

The most important biological changes which have to be monitored is the mechanism of ageing in the human body where the mitochondria play a major role. Hydrogen peroxide (H2O2) is one of the important markers for the reactive oxygen species (ROS), which denatures the protein and DNA, that was the main contributory factor of ageing. So, it is very important to monitor H2O2 levels in the biological samples. Herein, we reported the preparation of 1D graphene nanoribbon/cobalt oxide nanorod (GNR/Co3O4) based nanocomposite-modified electrochemical sensor for H2O2. Firstly, GNR was synthesized by oxidative unzipping of multiwalled carbon nanotubes (MWCNTs). Secondly, cobalt oxide nanorods (Co3O4) were grown onto GNR by a chemical reduction process. As-prepared nanocomposite was characterized by UV-Visible spectroscopy (UV-Vis) and HR-TEM. Electrochemical properties of GNR/Co3O4-coated electrode were studied by cyclic voltammetry (CV) which showed two redox peaks at 0.93 and 0.88 V in phosphate buffer solution. Next, the electrocatalytic activity of GNR/Co3O4-coated electrode was studied against H2O2 oxidation. The electrochemical studies revealed that GNR/Co3O4-coated electrode exhibited high electrocatalytic activity for H2O2 oxidation at 0.925 V. This sensor showed a linear response for H2O2 oxidation from 10 to 200 μM. The limit of detection (LOD) was calculated to be 1.27 μM. The selectivity of the sensor was also studied with other biomolecules associated in the human body, and the results showed that interference effect is negligible. Thus, the proposed GNR/Co3O4-modified electrode can be used for H2O2 detection with excellent stability and selectivity.