Fe ₃ O ₄ @MoS ₂ /MoO ₃ /rGO Nanocomposite for Ammonia Gas‐Sensing at Room Temperature

ABSTRACT In the present study, MoS 2 /rGO hybrid support nanosheets have been prepared by a convenient hydrothermal method, followed by the synthesis of iron oxide nanoparticles by the co‐precipitation method on the MoS 2 /MoO 3 /rGO hybrid support to form Fe 3 O 4 @MoS 2 /MoO 3 /rGO nanocomposite. The characterization of the nanocomposite revealed structural, morphological, and surface chemical properties, which typically affect its sensing performance. The nanocomposite was then tested as a sensor material for ammonia gas sensing at room temperature, 50, 100 and 150°C. The enhanced sensing behavior is attributed to the synergistic interaction between Fe 3 O 4 nanoparticles and the MoS 2 /MoO 3 /rGO hybrid nanosheet support, which provides additional active sites, leading to efficient charge transfer, and promotes strong surface reactions with ammonia molecules under ambient conditions. The Fe 3 O 4 @MoS 2 /MoO 3 /rGO nanocomposite sensor exhibits promising NH 3 gas‐sensing performance, achieving a 67% response at 50 ppm and a low detection limit of 0.25 ppm at room‐temperature.