Rational Design of NiCo2O4/Ti3C2 MXene Heterostructure for Unmanned Aerial Vehicles-Enabled Real-Time CO Monitoring

The integration of gas sensors with small unmanned aerial vehicles (UAVs) has attracted widespread attention in atmospheric chemistry, industrial emission monitoring and environmental protection. However, conventional metal oxide semiconductor gas sensors currently installed on UAVs exhibit issues such as inadequate sensitivity, long response times, and unsatisfactory stability. In this direction, NiCo2O4 inserted two-dimensional layered Ti3C2 MXene have synthesized using a facile hydrothermal method for CO detection. The density functional theory (DFT) calculations were first employed to explore CO adsorption behaviors, revealing that the adsorption energy of gas molecules is significantly reduced after the combination of NiCo2O4 and MXene. The optimized MXene incorporation effectively prevents nanoparticle agglomeration, significantly increasing the specific surface area and exposing abundant active sites for gas adsorption. As a result, the hybrid sensor exhibited more than five times higher response toward 100 ppm CO at 110 °C with shorter response time (39 s) than pristine NiCo2O4. Through in situ Raman spectroscopy analysis, we elucidated the rapid adsorption–desorption of gas molecules on heterostructures. Furthermore, we successfully implemented the developed NiCo2O4/Ti3C2 MXene sensor on a compact drone platform, enabling real-time three-dimensional spatial mapping of CO concentrations. This work not only advances the design of high-performance gas sensing materials but also showcases the practical viability of drone-mounted MXene sensors for real-time 3D air quality mapping, paving the way for smart environmental monitoring systems.