Ppb-level unsymmetrical dimethylhydrazine detection based on In₂O₃ hollow microspheres with Nd doping

As one of main high-energy fuels for rocket launching, unsymmetrical dimethylhydrazine (UDMH) and its decomposition products do harm to environment and human health. It is significant to develop a device to monitor its leakage. In this work, a UDMH gas sensor based on In₂O₃ hollow microspheres with Nd dopant was fabricated. The pure, 1.0 mol%, 3.0 mol% and 5.0 mol% Nd doped In₂O₃ were synthesized via one-step solvothermal method. Among them, 3.0% Nd-In₂O₃ based sensor exhibits the highest response toward UDMH vapor. Its response value to 100 ppm UDMH is 183.3 at optimal working temperature of 250 °C, 6.8 times higher than that of pure In₂O₃ (26.8). Besides high response to UDMH, the 3% Nd-In₂O₃ based sensor represents excellent selectivity, rapid response speed (2 s) and ultra-low theoretical LOD to UDMH (0.28 ppb). The improved gas sensing performance via Nd doping could be attributed to the enhanced specific surface area, increased concentration of adsorbed oxygen and improved adsorption capacity for UDMH molecular on the surface. The excellent sensing performance of Nd doped In₂O₃ hollow microspheres makes it a promising candidate for real-time UDMH detection.