Fabrication and sensing performance of a highly sensitive room-temperature NO₂ gas sensor based on few-layer Ti₃C₂ MXene/WO₃ nanoparticle composites

NO₂ is a highly irritating toxic gas that poses risks to respiratory health, and its concentration fluctuations in exhaled breath are associated with respiratory diseases such as asthma. Thus, developing high-performance room-temperature NO₂ gas sensors is of great practical significance. In this study, a room-temperature NO₂ gas sensor based on few-layer Ti₃C₂ MXene/WO₃ nanoparticles composites was developed. WO₃ nanoparticles were synthesized via a one-step hydrothermal method and physically mixed with few-layer Ti₃C₂ MXene. The crystal structure, surface morphology, and NO₂ sensing performance of the composite materials were characterized. The results show that the optimized Ti₃C₂ MXene/WO₃ composites exhibited excellent gas-sensing properties with a response of 8.3 (<i>dR</i>/<i>R</i>_a) to 1 ppm NO₂, which is 23 times higher than that of pure WO₃ (response of 0.36). Further tests verified that the optimized sensor had excellent repeatability, long-term stability, and good selectivity. This work demonstrates the potential of the WO₃/Ti₃C₂ MXene composite for room-temperature NO₂ detection.