Room‐Temperature Ammonia Sensing Using a Novel CuSeO 3 /MXene Nanocomposite With Enhanced Selectivity and Sensitivity

Two‐dimensional Ti 3 C 2 T x MXene continues to attract attention for gas‐sensing technologies due to its excellent electrical conductivity, abundant surface terminations, and rapid charge–transfer characteristics. In this study, a CuSeO 3 /MXene nanocomposite was synthesized through a hydrothermal route and evaluated as a room‐temperature chemiresistive sensor for ammonia (NH 3 ). The synergistic combination of CuSeO 3 , offering strong redox activity and abundant adsorption sites, with MXene, providing a high surface area and efficient electron‐transport pathways, significantly improves sensing performance. The nanocomposite exhibits a response of 78.9% toward 500 ppm NH 3 , rapid response‐recovery behavior with a low LOD of 1.808 ppm, and excellent selectivity against interfering gases such as ethanol, acetone, methanol, and formaldehyde. The sensor operates efficiently in the 50–500 ppm range ( R 2 = 0.9947), suitable for industrial and food monitoring applications. The enhanced behavior is attributed to effective NH 3 adsorption and charge‐carrier modulation at the CuSeO 3 /MXene interface, supported by the formation of a metal‐semiconductor junction under ambient conditions. These results demonstrate that the CuSeO 3 /MXene nanocomposite is a promising candidate for high‐performance room‐temperature NH 3 sensing applications.