Room-temperature methane sensor based on Pt–ZnSnO3–rGO ternary composite and vacuum ultraviolet excitation

Traditional metal oxide semiconductor (MOS) methane sensors rely on high-temperature thermal excitation to drive reactions, leading to safety hazards and poor device stability. Replacing thermal excitation with ultraviolet (UV) light excitation has been proposed as an effective strategy to mitigate these issues. However, current research on UV light excitation primarily focuses on the UVA–UVC bands, with limited studies on higher-energy vacuum ultraviolet (VUV) excitation. To address this research gap, this study innovatively employs 116.5 nm VUV light as the excitation source and constructs a room-temperature methane sensor using a Pt–ZnSnO₃–rGO (reduced graphene oxide) ternary composite material as the sensing layer. The performance of the resulting sensor was systematically evaluated, along with an in-depth elucidation of its sensing mechanism. The experimental results indicate that the fabricated sensor exhibits excellent performance at room temperature, with a response value of 58.1% toward 5000 ppm methane, a response time of 101 s, and a recovery time of 104 s. Additionally, it demonstrates satisfactory repeatability and excellent selectivity. Through material characterization and mechanism analysis, a novel synergistic catalytic mechanism under VUV illumination is revealed: the VUV light directly activates CH₄ and excites the semiconductor material; Pt catalyzes the reaction efficiently with the aid of VUV light; and rGO facilitates charge separation and gas diffusion. The synergistic interaction among these three components establishes an effective low-temperature methane catalytic pathway, significantly lowering the reaction energy barrier. This work provides a new direction for the development of room-temperature methane detection.