Ppb-Level H₂S Gas Sensor Based on Li-Doped CuO Nanoparticles Compounded on Graphene at Room Temperature

The development of a H₂S gas sensor that exhibits high response and a low detection limit remains a highly anticipated goal in the field. In this work, Li-doped CuO nanoparticles compounded on graphene were successfully prepared by the solvothermal method for efficient H₂S gas detection. The lattice structure, microstructure, elemental distribution, and chemical states of rGO-CuO-Li were systematically characterized by XRD, SEM, EDS, and XPS. The results confirmed the successful synthesis of Li-doped CuO nanoparticles compounded on graphene. The gas sensing test results demonstrated that 4 mol % rGO-CuO-10 mol % Li (CCuLi-2) exhibited excellent gas sensing performance for H₂S gas. At room temperature, the CCuLi-2 nanocomposite material exhibited a remarkably high response value of 220.1 to 10 ppm H₂S gas, which was 30.6 times that of pure CuO. In addition, the sensor achieved a breakthrough in its detection limit, enabling it to detect 1 ppb H₂S gas with a response value of 1.54. Meanwhile, the CCuLi-2 demonstrated high selectivity and superior long-term stability for H₂S detection. This research provides a novel reference for the design and development of H₂S sensors with low detection limits and high sensitivity.