Noble metal-free modified electrode of exfoliated graphitic carbon nitride/ZnO nanosheets for highly efficient hydrogen peroxide sensing

- The g-C3N4/ZnO nanosheets were synthesized as a noble metal-free H2O2 sensor.
- The high electrocatalytic property of g-C3N4/ZnO nanosheets was demonstrated.
- The g-C3N4/ZnO/FTO electrode revealed the high sensitivity of 540.8 μA mM−1 cm−2.
- The linear range was obtained from 0.05 to 14.15 mM towards H2O2.

Graphitic carbon nitride (g-C3N4)/ZnO nanosheets were coated on the surface of fluorine-doped tin oxide (FTO) glass as a noble metal-free g-C3N4/ZnO/FTO electrode, which was used for the determination of hydrogen peroxide (H2O2). The exfoliated g-C3N4 nanosheets were firstly prepared and then ZnO nanosheets were grown on g-C3N4 nanosheets by a microwave-assisted hydrothermal synthesis. The g-C3N4 nanosheets combined with ZnO nanosheets can greatly improve the adsorption of hydrogen peroxide and increase the conductivity of materials as well. The g-C3N4/ZnO nanosheets were characterized by powder X-ray diffraction (XRD), scanning electron microscopic (SEM), transmission electron microscopic (TEM), and X-ray photoelectron spectroscopy (XPS) analysis. Meanwhile, electrochemical measurements of the g-C3N4/ZnO/FTO electrode were utilized to investigate the amperometric sensing of hydrogen peroxide. The prepared g-C3N4/ZnO/FTO electrode revealed the sensitivity of 540.8 μA mM−1 cm−2 at −0.5 V with the linear response range from 0.05 to 14.15 mM, which even was superior to some noble metal-decorated H2O2 sensors. Additionally, the g-C3N4/ZnO/FTO electrode also showed the reliable operational and environmental stability for electrochemical reduction of H2O2.

We designed and prepared the g-C3N4/ZnO/FTO electrode as a noble metal-free hydrogen peroxide sensor for the first time. The prepared g-C3N4/ZnO/FTO electrode revealed the high sensitivity of 540.8 μA mM−1 Cm−2 and wide linearity range from 0.05 to 14.15 mM, which was comparable with noble metal modified electrodes. And the g-C3N4/ZnO/FTO electrode also exhibited the reliable operational and environmental stability.131