Abstract
Gas sensing is critical for environmental monitoring, industrial safety, and healthcare diagnostics, particularly for detecting hazardous or significant gases like volatile organic compounds (VOCs), ammonia, and formaldehyde [1, 2, 3, 4, 8, 10]. Traditional gas sensors often require external power sources, which can limit their portability and deployment in remote or harsh environments. Self-powered gas sensors, which harvest energy from their surroundings, offer a promising solution to this limitation. Triboelectric nanogenerators (TENGs), devices that convert mechanical energy into electrical energy through the coupling of triboelectrification and electrostatic induction, have emerged as effective power sources and active sensing components for self-powered gas detection systems [20, 24, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40]. This review provides a comparative analysis of the sensing mechanisms employed in TENG-based self-powered gas sensors. It examines how the interaction between target gases and the TENG's materials, or integrated sensing layers, leads to detectable changes in the TENG's electrical output. Key mechanisms discussed include changes in triboelectric properties, modulation of integrated resistive or capacitive sensing layers by the TENG's output, and gas ionization effects. Challenges and future perspectives for the development of highly sensitive, selective, and stable self-powered gas sensors based on TENGs are also addressed.