High-Sensitivity Room-Temperature Detection of H₂S Using ZnO/Ti₃C₂T_X Nanocomposite: Potential Applications in Exhaled Gas Monitoring

The detection of hydrogen sulfide (H₂S) in exhaled breath at room temperature is essential for health monitoring and disease diagnosis. This study investigates a ZnO/Ti₃C₂T_X nanocomposite synthesized by combining ZnO nanoparticles, prepared by a hydrothermal method, with Ti₃C₂T_X MXene. Experimental results demonstrate that the ZnO/Ti₃C₂T_X nanocomposite sensors exhibit excellent H₂S detection performance at room temperature with high sensitivity, rapid response time, and robust recovery capability. Specifically, the ZnO/Ti₃C₂T_X-1.0 wt % nanocomposite sensor shows a response of 85.116 at 5 ppm of H₂S, which is 14-fold and 35-fold greater than that of pure ZnO and Ti₃C₂T_X MXene, respectively. The sensor exhibits a rapid response (50 s) and recovery time (115 s) at 100 ppb of H₂S. Additionally, it shows exceptional sensitivity to H₂S at low concentrations, with a detection limit as low as 1 ppb. Based on the excellent sensing performance, oral exhaled gas detection demonstrates that the sensor effectively differentiates H₂S levels in healthy and patient breath samples. These findings highlight the potential of the ZnO/Ti₃C₂T_X nanocomposite in exhaled H₂S detection at room temperature, offering new insights for developing ultrasensitive biogas sensors.