Computational screening and experimental fabrication of MoSe2/3d–TMOS heterojunction for room-temperature gas sensor

Heterogeneous engineering is an efficient method to overcome the poor adsorption performance of MoSe2 materials. In this work, the screening process for a suitable transition metal oxide semiconductor with 3d orbital (3d–TMOS) was performed based on the work of adhesion and band edges positions with reference to the MoSe2 material. Then, the gas sensor performance of the suitable composite system was further tested and discussed. The results show that the Cr2O3, Fe2O3 and Co3O4 surface present good interfacial binding strength with MoSe2 compared with other 3d–TMOSs. And the MoSe2/Co3O4 system was selected considering the suitable band edges positions. The as-fabricated MoSe2/0.5–Co3O4 nanocomposite exhibits excellent sensitivity to NO2 at room temperature. Moreover, the MoSe2/0.5–Co3O4 nanocomposite exhibits excellent linear response (R2 = 0.985), selectivity, repeatability, and long–term stability to NO2. The improvement mechanism of gas sensor performance can be mainly attributed to the fast charge extraction rate of type-II heterojunction and greatly sensitive of built-in potential barrier to the carrier density in the MoSe2/0.5–Co3O4 nanocomposite. This research provides a promising method to select the candidates for gas sensor using the combined DFT calculations and experiments.