Ultrafast, Highly Sensitive, and Selective Detection of p‑Xylene at Room Temperature by Peptide-Hydrogel-Based Composite Material

A peptide/carbon dot (CD) composite xerogel is used as a selective p-xylene VOC (volatile organic compound) sensor. The fiber formation by the peptide allows us to attain a semiconducting property, whereas the presence of the CD amplifies the sensitivity. The selective detection of p-xylene is achieved at a very low concentration (response ≈ 96% for 50 ppm) with an ultrafast response (630 ms) and recovery (540 ms). The sensor is also able to detect p-xylene within crude oil, proving its industrial application. In comparison with the available VOC sensors, this work stands out as a low-cost, sensitive, and selective room-temperature p-xylene sensor with ultrafast sensing ability.