Fabrication of TiO₂/CuO Heterostructure Nanostructures for Fast Detection of Ammonia Gas at Room Temperature

In this study, TiO2/CuO heterostructure nanomaterials for ammonia gas-sensing applications operating at room temperature were prepared using hydrothermal synthesis. The TiO2/CuO composite material was systematically characterized and analyzed using XRD analysis, SEM imaging, TEM observations, and XPS measurements. The TiO2/CuO composite material exhibited a significant specific surface area alongside a substantial degree of porosity. The TiO2/CuO sensor demonstrated optimal sensing performance toward ammonia gas with 30 wt % CuO content, featuring a low detection limit, remarkable stability over extended periods, consistent reproducibility, and rapid response/recovery kinetics at room temperature. The improvement in NH3 gas sensing performance was attributed to the enhanced surface area, which provided additional active sites for gas adsorption on the material surface. Additionally, the formation of p–n heterojunctions in the interface region of TiO2/CuO nanocomposites played a crucial role in enhancing sensing performance. Furthermore, first-principles calculations revealed the improvement in NH3 gas sensing performance through the TiO2/CuO heterostructure. The TiO2/CuO sensor holds practical significance for ammonia gas sensing applications.