Vanadium dioxide/molybdenum telluride heterojunction gas sensor for methane detection

In this paper, a new sensor for methane detection based on vanadium dioxide (VO2)-molybdenum telluride (MoTe2) nanocomposites is reported for the first time. The VO2 layered structure and MoTe2 silver ear like structure were prepared using a hydrothermal method. The morphology, elemental composition, and valence states of VO2-MoTe2 composites were investigated through transmission electron microscope (TEM), electron microscope (SEM), scanning X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The characterization results proved the successful synthesis of the composites. A series of tests were conducted on the methane gas sensing performance of VO2-MoTe2 sensors at room temperature by building a gas testing platform. The results show that the sensor has outstanding gas sensing performance for methane under the interference of various gases, such as high sensitivity, fast response/recovery, selectivity, good repeatability and stability. The gas sensing mechanism of VO2-MoTe2 nanocomposite sensors for enhancing methane performance was discussed in detail through characterization and testing results. The potential sensing mechanism of the sensor for methane can be attributed to the heterojunction and synergistic effect formed between p-type VO2 and n-type MoTe2.