A WO ₃ /Ti ₃ C ₂ T _<i>x</i> MXene Composite Sensor for 2-Heptanone Gas Detection at Room Temperature

The development of gas sensors that can operate at room temperature while demonstrating high sensitivity to volatile gases indicative of food spoilage continues to pose a significant challenge. In this study, WO₃ was in situ grown on the surface and interlayers of Ti₃C₂T_<i>x</i> MXene through a solvothermal method, successfully synthesizing WO₃/Ti₃C₂T_<i>x</i> MXene composite materials. The fabricated WO₃/Ti₃C₂T_<i>x</i> MXene gas sensor exhibited a remarkable response value of 3.25 toward 50 ppm 2-heptanone at room temperature (25 °C), representing a 2.4-fold enhancement compared to pure WO₃ nanosheets (1.34). Furthermore, the sensor demonstrated exceptional selectivity and outstanding reproducibility toward 2-heptanone, attributable to the distinctive hierarchical architecture of WO₃/Ti₃C₂T_<i>x</i>, which provides an extensive specific surface area and synergistic enhancement from the p-n heterojunction. The successful fabrication of WO₃/Ti₃C₂T_<i>x</i> composites establishes a novel strategy for developing advanced room-temperature gas sensing materials with superior performance.