Superior triethylamine-sensing properties based on TiO2/SnO2 n-n heterojunction nanosheets directly grown on ceramic tubes

A highly sensitive and selective gas sensor towards triethylamine (TEA) has been successfully fabricated by designing n-n heterojunctions consisting of SnO2 nanosheets and TiO2 nanoparticles. The SnO2 nanosheets with the thickness about 15 nm were directly grown on Al2O3 ceramic tubes by a simple hydrothermal process. After the formation of n-n heterojunctions by employing PLD method, the TiO2 nanoparticle/SnO2 nanosheets heterojunctions exhibit high sensing properties to TEA gas. The as-prepared ST3 (SnO2/TiO2 3000) sensor response could reach to 52.3 at relatively low temperature (260 °C) when exposed to 100 ppm TEA gas, which is much higher than that of pure SnO2 nanosheet sensor (∼3@100 ppm TEA@320 °C). Compared with the pure SnO2 nanosheet sensor (S sensor), the depletion layer formed at the n-n heterojunctions interface in TiO2/SnO2 sensor can greatly increase the resistance in air and decrease the resistance in TEA gas. Due to the general working principle and controllable growth strategy, this work provides a way for developing the chemiresistive gas sensors.