Highly sensitive and low working temperature detection of trace triethylamine based on TiO2 nanoparticles decorated CuO nanosheets sensors

Considering the poor sensing abilities and high working temperatures for trace triethylamine (TEA) detection, design and fabrication of TEA gas sensors with high sensitivity and low power consumption are still desired. Decorating p-type substrate with n-type semiconductor to form p-n junction is considered to be an effective approach to enhance their sensing abilities. Herein, regular "droplets on salix leaf" like CuO/TiO 2 nanocomposites were designed and successfully synthesized using a two-step method including a water bath treatment and a TiF 4 solution etching process. Surface characterizations indicated that the CuO substrate exhibited a salix leaf like nanosheets structure with massive TiO 2 nanoparticles (about 11 nm) decorated on its surface. Excitingly, gas sensing results showed that the CuO/TiO 2 sensors exhibited a high sensing response of 12.7–5 ppm TEA at a low working temperature (160 °C) and possessed a low detection limit (0.5 ppm). The sensing mechanism was also proposed and attributed to the massive highly dispersed p-n junctions between CuO and TiO 2 nanoparticles, which could significantly change the electrical conductivity and oxygen adsorption abilities. In addition, X-ray photoelectron spectroscopy and Electron paramagnetic resonance measurements confirmed the existence of large amounts of surface oxygen vacancy regions and chemisorbed and dissociated oxygen species, which were beneficial to their gas sensing abilities. This work provides a new strategy to fabricate highly sensitive trace TEA gas sensing materials with low working temperatures, which will also promote the application of p-type gas sensors.