Self-template synthesis of mesoporous Au-SnO₂ nanospheres for low-temperature detection of triethylamine vapor

The development of metal oxide semiconductor gas sensor for low-temperature detection of hazardous gases (e.g., triethylamine, TEA) is highly desirable, but still challenging. Herein, a self-template synthesis strategy for mesoporous Au-SnO₂ nanospheres was developed using nontoxic, renewable and low-cost plant polyphenol as a main chelating agent, tin ions and chloroauric acid as a metal source. Because of the strong chelate ability of polyphenol, a stable Au/tin-polyphenol-formaldehyde sphere is obtained and used as a precursor. After direct calcination process, Au-SnO₂ materials with mesoporous crystalline framework, uniform diameter (~120 nm) and high specific surface area (105.2 m²/g) are successfully prepared. The mesoporous Au-SnO₂ nanospheres are further used for TEA sensing. They show high response (5.16) at a low temperature (50 ℃) toward TEA. The detection limit was 0.11 ppm. The decoration of Au species can effectively decrease the activation energy and lower the working temperature. After integration with Bluetooth, the gas sensor can be used for wireless monitoring TEA with a low concentration (10–50 ppm) and fast response (~ 30 s). This proposed strategy can be used for mesoporous noble metal-metal oxides and further boost the sensing performance of gas sensor.