Heterogeneous Co3O4/Carbon Nanofibers for Low Temperature Triethylamine Detection: Mechanistic Insights by Operando DRIFTS and DFT

Abstract Metal oxide semiconductors (MOS) have been extensively investigated for the detection of toxic organic amines. However, the high working temperature of metal oxide semiconductors (MOS) remains a challenge that greatly limits their potential in sensor technology. Meanwhile, the sensing mechanism of triethylamine (TEA) has not been fully understood. In this work, the authors report the design of heterogeneous Co 3 O 4 /carbon nanofibers (Co 3 O 4 /CNFs) and their utilization toward TEA detection at low temperature. With an optimized loading density of Co 3 O 4 nanocrystals, the sensor based on Co 3 O 4 /CNFs, which exhibits remarkable response to TEA even at room temperature, delivers the best response of Co 3 O 4 /CNFs at 150 °C. Notably, the response of Co 3 O 4 /CNFs is three times higher than that of pristine Co 3 O 4 . More importantly, they, for the first time, elucidate the TEA sensing mechanism via operando diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and density functional theory (DFT) calculations, revealing that the oxidation of TEA undergoes a two‐step process. This work not only paves the way to design high performance sensing materials, but also contributes to the fundamental understanding of a sensing mechanism.