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. Unsymmetrical dimethylhydrazine (1,1-dimethylhydrazine, UDMH) is a colorless, highly toxic compound. It has been classified as 2B human carcinogen by the International Agency for Research on Cancer (IARC). The National Institute for Occupational Safety and Health (SLOSH) also regulates the UDMH concentration limitation of 0.06 ppm in workplace. Therefore, it is urgent to fabricate a device for detecting the UDMH leakage timely during its storage and transport. In our work, Nd doped In2O3 hollow microspheres based chemiresistive gas sensor for the monitoring of UDMH was developed, which will promote the practical applications for gas sensor.