Monitoring the hydrogen gas (H2) level is highly important in a wide range of applications. Oxide-carbon hybrids have emerged as a promising material for the fabrication of gas sensors for this purpose. Here, for the first time, graphitic carbon nitride (g-C3N4)-doped zinc oxide nanorods (ZNRs) have been grown on silicon (Si) pyramid-shaped surfaces by the facile hydrothermal reaction method. The systematic material analyses have revealed that the g-C3N4 nanostructures (NS) have been consistently incorporated into the ZNRs on the pyramidal silicon (Py-Si) surface (g-C3N4-ZNRs/Py-Si). The combined properties of the present structure exhibit an excellent sensitivity (∼53%) under H2 gas exposure, better than that of bare ZNRs (12%). The results revealed that the fine incorporation of g-C3N4 into ZNRs on the Py-Si surface improves the H2 gas sensing properties when compared to that of the planar silicon (Pl-Si) surface. The doping of g-C3N4 into ZNRs increases the electrical conductivity through its graphene-like edges (due to the formation of delocalized bonds in g-C3N4 during carbon self-doping), as revealed by FESEM images. In addition, the presence of defects in g-C3N4 induces the gas adsorption properties of ZnO through its active sites. Moreover, the integration of the 1D structure (g-C3N4-ZNRs) into a 3D pyramidal structure opens up new opportunities for low-cost H2 gas sensing at room temperature. It is an easy way to enhance the gas sensing properties of ZNRs at room temperature, which is desirable for practical H2 sensor applications.
Keywords: 1D/3D structure; ZnO nanorods on pyramidal Si; g-C3N4-ZNRs hybrids; g-C3N4-ZNRs hydrogen sensors; g-C3N4-ZNRs on Si pyramids.