Enhanced Triethylamine Detection at Room Temperature Using a Layered MoS₂ Nanosheet-Coated PPy Nanorod: A...

The rapid and reliable detection of triethylamine (TEA), a toxic, explosive, volatile organic compound at room temperature, is highly significant for food safety, environmental, and human health monitoring. This manuscript reports a layered molybdenum disulfide (MoS₂) nanosheet-coated polypyrrole (PPy) nanorod-based heterostructure sensor (MsPy) which offers superior sensing properties toward TEA at room temperature (25 °C). Herein, different MsPy nanocomposites were synthesized, followed by a controlled sulfidation reaction through dissolution, diffusion, and regrowth mechanisms. Optimizing the ratio of the precursor of molybdenum trioxide (MoO₃/PPy) is crucial for achieving effective deposition of a layered MoS₂ nanosheet on the PPy surface. The as-prepared MoS₂ nanosheet-coated PPy sensor (MsPy_40) enables one to selectively detect trace TEA vapor at 25 °C with a detection lower limit of 0.5 ppm. The MsPy_40 sensor exhibits 17 times higher response than the pristine MoS₂ nanosheet to 50 ppm TEA, with rapid response (∼3.9 s) and recovery (∼19.6 s), along with better stability, good selectivity, and remarkable repeatability. The significantly enhanced sensing performance is attributed to the unique surface morphology of the layered MoS₂ nanosheet-coated PPy nanorod and the formation of a p-n heterojunction between PPy and MoS₂.