Sensitive and selective detection of plasticizer vapors with modified-SnO2 hollow nanofibers for electrical fire warning

Monitoring the vapor concentration of semi-volatile plasticizers released from overheated PVC cables is vital for early warning of electrical fires. In this work, SnO2 hollow nanofibers were prepared and modified with various oxides via a facile impregnation-calcination method. SnO2 hollow nanofibers loaded with 2.8 at.% In2O3 and 5.0 at.% ZnO exhibited excellent response to the fire signature gases, Dioctyl phthalate (DOP) and 2-Ethylhexanol (2-EH) plasticizers, whilst NiO modification deteriorated the sensing performance. A maximum response of 44 and 27 to 100 ppm DOP and 2-EH, respectively, as well as a short response time (3-5 s), were achieved. Moreover, the cross-sensitivity towards common interfering gases such as ethanol and H-2 was greatly reduced. Large-scale simulation tests showed that the modified sensors started to respond to the fire hazard earlier than the alarm of a conventional smoke detector went off, particularly at lower cable temperatures.