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

Area of Science:

• Materials Science
• Chemical Engineering
• Sensor Technology

Background:

• Developing highly sensitive and selective hydrogen sulfide (H₂S) gas sensors with low detection limits is crucial for environmental monitoring and industrial safety.
• Existing sensors often face challenges with sensitivity, selectivity, and detection limits, necessitating innovative material design.

Purpose of the Study:

• To synthesize and characterize Li-doped CuO nanoparticles compounded on graphene for enhanced H₂S gas sensing.
• To evaluate the gas sensing performance, including response, detection limit, selectivity, and stability, of the developed nanocomposite material.

Main Methods:

• Solvothermal synthesis method was employed to prepare Li-doped CuO nanoparticles on reduced graphene oxide (rGO).
• Material characterization involved X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), and X-ray Photoelectron Spectroscopy (XPS).
• Gas sensing performance was tested at room temperature using a custom-built gas sensing setup.

Main Results:

• Successful synthesis of Li-doped CuO nanoparticles integrated with graphene (rGO-CuO-Li) was confirmed through material characterization.
• The optimized nanocomposite (4 mol % rGO-CuO-10 mol % Li, CCuLi-2) demonstrated a high response (220.1 to 10 ppm H₂S) at room temperature, significantly outperforming pure CuO.
• A breakthrough detection limit of 1 part per billion (ppb) for H₂S was achieved with a response value of 1.54.
• The CCuLi-2 sensor exhibited excellent selectivity and long-term stability for H₂S detection.

Conclusions:

• Li-doped CuO nanoparticles on graphene offer a promising platform for developing highly sensitive and low-detection-limit H₂S gas sensors.
• The CCuLi-2 nanocomposite represents a significant advancement in H₂S sensing technology, addressing key performance limitations of previous materials.
• This research provides valuable insights for designing next-generation gas sensors with enhanced performance characteristics.