Enhanced Xylene Sensing Performance of Fe‐Doped NiO Nanosheet Arrays via In Situ Growth

Xylene is a hazardous volatile organic compound (VOC) widely present in industrial environments, and achieving sensitive and stable detection of xylene remains a significant challenge for gas sensors. Here, a one‐step hydrothermal route was employed to in situ grow p‐type Fe‐doped NiO nanosheet arrays on ceramic tubes for xylene detection. Remarkably, trace Fe‐doping (0.2%) NiO leads to a threefold enhancement in response to 100 ppm xylene, compared with pristine NiO. This improvement is attributed to the Fe 3+ ‐induced regulation of the Ni 3+ /Ni 2+ ratio and surface oxygen states, particularly the enrichment of reactive chemisorbed oxygen species. Structural and spectroscopic analyses reveal that Fe incorporation subtly modulates the local electronic environment of NiO without disrupting its crystal framework. The optimized Fe‐doped NiO sensor shows high selectivity toward xylene, a wide detection range (10–200 ppm), and excellent humidity resistance, demonstrating its potential for practical VOC monitoring. This work highlights that low‐level Fe doping can effectively tailor the surface electronic structure of strongly correlated p‐type oxides, offering a viable strategy for high‐performance gas sensors.