Nitrogen-Doped Graphene-Encapsulated Nickel Cobalt Nitride as a Highly Sensitive and Selective Electrode for Glucose and Hydrogen Peroxide Sensing Applications.

To explore a natural nonenzymatic electrode catalyst for highly sensitive and selective molecular detection for targeting biomolecules is a very challenging task. Metal nitrides have attracted huge interest as promising electrodes for glucose and hydrogen peroxide (H2O2) sensing applications due to their exceptional redox properties, superior electrical conductivity, and superb mechanical strength. However, the deprived electrochemical stability extremely limits the commercialization opportunities. Herein, novel nitrogen-doped graphene-encapsulated nickel cobalt nitride (Ni xCo3- xN/NG) core-shell nanostructures with a controllable molar ratio of Ni/Co are successfully fabricated and employed as highly sensitive and selective electrodes for glucose and H2O2 sensing applications. The highly sensitive and selective properties of the optimized core-shell NiCo2N/NG electrode are because of the high synergistic effect of the NiCo2N core and the NG shell, as evidenced by a superior glucose sensing performance with a short response time of <3 s, a wide linear range from 2.008 µM to 7.15 mM, an excellent sensitivity of 1803 µA mM-1 cm-2, and a low detection limit of 50 nM (S/N = 3). Furthermore, the core-shell NiCo2N/NG electrode shows excellent H2O2 sensing performances with a short response time of ∼3 s, a wide detection range of 200 nM to 3.4985 mM, a high sensitivity of 2848.73 µA mM-1 cm-2, and ultra-low limit detection of 200 nM (S/N = 3). The NiCo2N/NG sensor can also be employed for glucose and H2O2 detection in human blood serum, promising its application toward the determination of glucose and H2O2 in real samples.