Effective detection of trace amount of explosive nitro-compounds by ZnO nanofibers with hollow structure

For the safe of both production and life, it is a key issue to detect explosives effectively. Here, we report that trace amount of nitro compounds can be detected by the sensor based on porous ZnO nanofibers. As a result, the response towards 200 ppb 4-nitrotoluene, 120 ppb 2, 4-dinitrotoluene and 30 ppm nitromethane are 6.8, 3.0 and 29, respectively. The detecting limit towards 2,4-dinitrotoluene and nitromethane is 3 ppb and 100 ppb. It is found that the sensing performance is greatly affected by the molecular structure of these nitro compounds under the same condition. That is, the sensing behavior is related to the alkyl group other than the nitro group. A reasonable sensing mechanism is proposed based on the theoretical and experimental results.