One-Step Electrospun WO₃/CuO p–n Heterojunction Nanocomposites for Ultrasensitive and Rapid H₂S Detection

Hydrogen sulfide (H₂S), a critical industrial gas, exhibits high toxicity, flammability, and strong corrosiveness, posing severe health risks at elevated concentrations. Consequently, developing highly sensitive and rapid-response detection methods is imperative. In this study, WO₃/CuO nanocomposites were synthesized via a one-step electrospinning technique, enabling the fabrication of high-performance H₂S gas sensors. The gas-sensing properties of WO₃/CuO nanocomposites for H₂S detection were systematically investigated. The composite sensor demonstrated optimal performance at 150 °C, with a CuO mass fraction of 5 wt % yielding the highest H₂S response. For 5 ppm of H₂S in air, the WO₃/CuO sensor exhibited a response value of 68.43%, with a rapid response time of 24 s and recovery time of 78 s at 150 °C. The enhanced H₂S sensing performance is attributed to the formation of p-n heterojunctions at the WO₃/CuO interface, which improves long-term stability. This mechanism was corroborated by in situ TEM and XRD analyses. Furthermore, the unique interaction between CuO and H₂S enhances low-concentration detection sensitivity. First-principles calculations revealed that the performance improvement arises from CuO sensitization effects and heterojunction formation. These findings provide novel insights and a theoretical foundation for advancing high-reliability gas sensor technologies.