An urchin-like SnO₂/NaNbO₃ nanocomposite with stable humidity-sensing properties at room temperature

An urchin-like nano-composite of SnO₂/NaNbO₃ was fabricated by the hydrothermal method and the influence of the Sn/Nb ratio in the samples on their humidity-sensing properties was investigated. The phases and morphologies of these composites and their elemental distributions were analyzed by X-ray diffraction scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The sensor based on the optimum Sn/Nb ratio of 1:0.4 exhibited remarkable humidity-sensing properties, including a good response (S = 4823.8) that was 8.72 times higher than that of the pure SnO₂ sensor (S = 553.01). The composites showed rapid response and recovery times (3/9 s), as well as good stability, linearity, and excellent selectivity. The fabrication and humidity-sensing mechanisms were systematically analyzed using analog computations and Nyquist diagrams, respectively. Compared with pure NaNbO₃ and SnO₂ sensors, our easily prepared SnO₂/NaNbO₃ sensor demonstrates good sensing properties and holds great promise for use in humidity-sensing applications.