Detection of vapors from overheated PVC cables with modified sea urchin-like ZnO for fire warning

Detecting the emitted vapors from overheated polyvinyl chloride (PVC) cables has proven to be an effective way to monitor early electrical fires. In this work, the vapors generated from both conventional and phthalate-free PVC cables were first examined. 2-ethylhexanol (2-EH) was found to be ubiquitously present and can serve as a universal signature gas for the overheated cables. Sea urchin-like ZnO was then prepared via a template-free hydrothermal route for sensing 2-EH. A facile immersion-calcination method was adopted to further modify ZnO, and different CuO/ZnO and Cr2O3/ZnO composites were obtained. The surface modification led to significant improvement in the response of the ZnO sensors to 2-EH. Cable fire simulation tests were also conducted to evaluate the response of optimized gas sensors to overheated conventional and phthalate-free cables in comparison with a typical smoke detector.