Fast response triethylamine sensor based on MOF-derived coral flower-like Fe-doped Co3O4

Triethylamine (TEA) is easily volatilized and poses a huge health hazard. Therefore, the rapid detection of TEA is of great significance in environmental protection and industrial applications. In this paper, coral flower-like Fe-doped Co3O4 was prepared using Co-MOF-74 as precursor. Compared with the pure Co3O4, Co3O4 doped with 2 mol% Fe has better gas sensing performance of TEA. At an optimum operating temperature of 199 °C, the response to 100 ppm TEA is 21.2, five times higher than that of the pure Co3O4, with a short response recovery time (13 s/15 s). In addition, the gas sensor exhibits a certain selectivity and anti-humidity stability, with a minimum detection limit of 1 ppm at operating temperature. The higher Co2+/Co3+ content in the sensor promotes the reaction of TEA with ionized oxygen, and amplifies the resistance change by adjusting the carrier concentration. Meanwhile, the introduction of Fe enriches the content of vacant oxygen and provides sufficient sites for the reaction and diffusion of TEA, further enhancing the sensing performance. In addition, Co3O4 and Fe2O3 combine to form p-n heterojunction, which helps to accelerate the gas adsorption-desorption process and improve the sensitive response speed. It creates a new design idea for the rapid detection of TEA gas by P-type metal-oxide semiconductors at relatively low operating temperatures.