Iron oxide-immobilized porous carbon nanofiber-based radio frequency identification (RFID) tag sensor for detecting hydrogen sulfide

Hydrogen sulfide (H2S) is the richest and stinkiest toxic gas found around coal mines, manholes, and semiconductor industries. However, there are not many studies on H2S detection around various industrial sites using wireless sensors. This study proposes an H2S wireless sensor system that communicates of the reader antenna and the sensor tag using 904 MHz activated radio frequency identification (RFID). The sensor tag is formed through an iron oxide-immobilized multiscale pore contained carbon nanofiber (Fe2O3-MPCNF)-based conductive paste. This wireless sensor tag has a large detection range (0.2 to 100 ppm) at 25 °C, is very sensitive to H2S gas (0.2 ppm or less), and is inexpensive to process. In addition, the sensor tag has a long operating range (5–40 cm) and excellent flexibility, and has excellent cycle stability (up to 35 days), making it practical for wearable devices for wireless detection.