Ultrasensitive and ultra-selective room-temperature HS gas sensor based on CuO-loaded InO 2D porous nanosheets.

Developing a cost-effective sensing material capable of detecting HS with ultra-sensitivity, ultra-selectivity, and low detection limits at room temperature remains highly anticipated. In this paper, two-dimensional (2D) porous InO nanosheets were prepared by a simple solvothermal method, and then CuO was modified on the InO surface by impregnation. The CuO/InO two-dimensional porous structure allows the fabricated sensor to be highly sensitive to HS at room temperature. Modifying CuO on InO significantly improves the response (R/R) to 10 ppm HS from 26 to 58000 at room temperature, while the response to other interfering gases (even 10 times the concentration of HS) not exceeding 5. After loading CuO, the response time was shortened from 56 s to 2 s, and the detection limit was reduced from 500 ppb to 50 ppb. Meanwhile, CuO/InO also has good repeatability and long-term stability, and full recovery can be achieved by pulse heating. The gas sensing and characterization results demonstrate that the excellent sensing performance of CuO/InO for HS at room temperature is due to the specific porous nanosheets morphology and structure of the material, the strong chemical affinity of alkaline CuO for HS, as well as the formation of p-n heterojunctions.