Enhanced Triethylamine Sensing Properties by Designing an α-Fe₂O₃/α-MoO₃ Nanostructure Directly Grown on Ceramic Tubes

Over the years, efforts have been made to develop simple and efficient techniques for the detection of triethylamine (TEA). In this task, to solve the problem that the powder easily falls off in the conventional MoO3 sensor preparation method, we directly grow α-MoO3 nanosheets with a high TEA sensing response on Al2O3 tubes through seed-layer-assisted growth technology and a hydrothermal method. Furthermore, to enhance the gas-monitoring performance of the α-MoO3 sensing element, nanoscale α-Fe2O3 particles were deposited on α-MoO3 nanosheets through a pulsed-laser-deposition method and the binary composite nanostructured materials were designed and fabricated. The morphology as well as structures of the α-Fe2O3/α-MoO3 materials have been characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, etc. The α-Fe2O3/α-MoO3 sensors exhibit a superior performance toward TEA than the pristine α-MoO3 sensor does, such as enhanced sensitivity and excellent stability. The mechanisms of enhanced sensing properties are discussed from the points of an α-Fe2O3/α-MoO3 N–N heterojunction based on the depletion layer model. Because of the general working principle and controllable growth strategy, this study provides a way to design and prepare chemical resistive gas sensors with high performance.