Au-sensitized metal–organic framework-derived indium-doped zinc oxide for highly enhanced trimethylamine sensing

Abstract

Preparation of a gas sensor capable of rapidly and accurately detecting trimethylamine is crucial for environmental monitoring, food safety and human health. In this study, Au-In-ZnO with an irregular nanoparticle structure was prepared using simple metal–organic-framework synthesis method and in-situ reduction process. The Au-In-ZnO sensor exhibited a high response of 260.2 to 100 ppm trimethylamine at 250 °C, which is 32 times higher than that of pristine ZnO (350 °C), with the optimal operating temperature lowered by 100 °C. Meanwhile, the sensor had a short response time (2 s), enabling it to quickly react to leaked trimethylamine during practical applications. Additionally, the sensor also possessed low detection limit (0.3 ppm, Rair/Rgas=2.0), high selectivity, excellent moisture resistance, good repeatability, and long-term stability. The mechanism of gas-sensitive properties enhancement was analyzed in combination with the conduction mechanism of hypervalent ions and the electronic and chemical sensitization of noble metals. This study provides a potential gas-sensitive material for the efficient measurement and rapid evaluation of trimethylamine.