Urchin-like TiO₂ Microspheres Coupled with MXene Nanosheets for CO₂ Detection

High Resolution Image Download MS PowerPoint Slide The CO 2 detection is crucial for both industrial and domestic use, as prolonged exposure to high levels can pose serious health risks. Recently, chemiresistive sensors have been demonstrated to be an affordable solution for detecting CO 2 in ambient conditions. In this study, a high-sensitivity chemiresistive sensor, consisting of an urchin-like TiO 2 microsphere coupled with a 2D MXene layer, was developed for CO 2 detection at room temperature over a wide range of 50–5000 ppm. By optimizing different aspects, such as unique urchin-like TiO 2 /MXene heterostructure, operating temperatures, and relative humidity (%RH), the urchin-like TiO 2 /MXene heterostructure sensors with a MXene concentration of 5 wt % exhibited high sensitivity and selectivity toward CO 2 gas under 50% RH at 30 °C temperature. The prepared urchin-like TiO 2 /MXene-based chemiresistive sensor exhibited a sensing response ( R ) of 30.69% for 500 ppm of CO 2 at 30 °C and 50% RH, significantly higher than that of pure TiO 2 (SR. 10%) and pure MXene (SR. 5%). Moreover, the gas sensor based on the TiO 2 /MXene heterostructure demonstrated significantly faster response and recovery times, with values of 82 and 92 s, respectively, compared to the pure TiO 2 and pristine MXene. The incorporation of MXene significantly improved sensing performance in terms of high sensitivity, long-term stability, and selectivity. These findings demonstrate the potential of MXene-related gas sensors for detecting food spoilage and other critical applications.