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.