Controllable Synthesis of Zn-Doped α-FeO Nanowires for HS Sensing.

One-dimensional Zn-doped α-FeO nanowires have been controllably synthesized by using the pure pyrite as the source of Fe element through a two-step synthesis route, including the preparation of Fe source solution by a leaching process and the thermal conversion of the precursor solution into α-FeO nanowires by the hydrothermal and calcination process. The microstructure, morphology, and surface composition of the obtained products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. It was found that the formation process of α-FeO is significantly influenced by the introduction of Zn. The gas sensing measurements indicated that the sensor based on 1% Zn-doped α-FeO nanowires showed excellent HS sensing properties at the optimum operating temperature of 175 °C. Notably, the sensor showed a low HS detection limit of 50 ppb with a sensor response of 1.5. Such high-performance sensing would be ascribed to the one-dimensional structure and high specific surface area of the prepared 1% Zn-doped α-FeO nanowires, which can not only provide a large number of surface active sites for the adsorption and reaction of the oxygen and HS molecules, but also facilitate the diffusion of the gas molecules towards the entire sensing materials.