Ammonia Gas Sensor Using Polypyrrole‐Coated TiO₂/ZnO Nanofibers

Highly porous polypyrrole (PPy)‐coated TiO 2 /ZnO nanofibrous mat has been successfully synthesized. The core TiO 2 /ZnO nanofibers have an average diameter of ca. 100 nm and the shell of ultrathin PPy layer has a thickness of ca. 7 nm. The NH 3 gas sensor using the as‐prepared material exhibited a fast response over a wide dynamic range and high sensitivity with a detection limit of 60 ppb ( S / N =3). Compared to conventional pristine PPy film, the improved performance in NH 3 detection can be attributed to the free access of NH 3 to PPy and a minimized gas diffusion resistance through the ultrathin PPy layer.