Mo₂C/MoO₃@rGO Ternary Nanocomposites as High-Performance Gas Sensor for Trace NH₃ Detection at Room Temperature

Mo 2 C/MoO 3 @rGO ternary nanocomposites were synthesized by a hydrothermal method, which can be applied to the high-sensitivity detection of low concentration of NH 3 at room temperature. Compared with pure MoO 3 and MoO 3 @rGO sensors, the Mo 2 C/MoO 3 @rGO sensors showed a significantly improved response to NH 3 at room temperature. Among them, the 6% Mo 2 C/MoO 3 @rGO sensor showed a response of up to 0.82 for 5 ppm of NH 3 with a response time of 87 s, which was 27.33 times higher than that of pure MoO 3 (0.03 in 154 s) and 5.86 times higher than that of MoO 3 @rGO (0.14 in 139 s). It also has high repeatability, selectivity, good long-term stability, and immunity to humidity. These optimizations of the gas-sensing properties of the material may be attributed to the ability of the heterojunction to modulate the material surface carriers, the chemical sensitization and good electrocatalytic ability of Mo 2 C, and the large specific surface area and high carrier mobility of rGO. The synergistic effect between these three materials allows the designed Mo 2 C/MoO 3 @rGO ternary composite to detect trace amounts of NH 3 at room temperature, making it possible to develop high-performance NH 3 gas sensors.