CuO-ZnO hetero-junctions decorated graphitic carbon nitride hybrid nanocomposite: Hydrothermal synthesis and ethanol gas sensing application

ZnO and CuO have attracted considerable attention for their potential application in gas sensors. However, they also have some disadvantages, such as high operating temperature and poor sensitivity. Graphitic carbon nitride (g-C3N4) has been widely used as metal-free catalyst and catalyst support in gas sensing field due to its unique chemical stability and excellent substrate characteristics. In this study, a one-step hydrothermal method was developed for the preparation of a CuO-ZnO/g-C3N4 ternary composite. The as-prepared samples were characterized by using the XRD, SEM, TEM, FTIR, UV–vis and XPS techniques. The analysis results indicated that the ternary composite was synthesized successfully. The morphological analyses demonstrated that the flake-like CuO and ZnO nanoparticles were wrapped and connected by g-C3N4 nanosheet. The as-prepared CuO-ZnO/g-C3N4 exhibited obviously enhanced sensing properties to ethanol, which were 1.34 times and 2.17 times higher than that of CuO-ZnO and CuO, respectively. The improving gas sensing properties were related to the valid p-n junctions of CuO-ZnO and excellent substrate effect of g-C3N4 nanosheet. •CuO-ZnO/g-C3N4 ternary nanocomposite was synthesized by using a facile hydrothermal method.•The nanoparticles ZnO and flake CuO distributed randomly on g-C3N4 surface with a close interface.•CuO-ZnO combined with g-C3N4 could obviously lower the optimal gas sensing test temperature to ethanol.