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.