Ni-doped WO3 flakes-based sensor for fast and selective detection of H2S

In this work, we report on the synthesis of Ni-doped WO 3 flakes by the hydrothermal method. The physical and chemical properties of the synthesized Ni-doped WO 3 flakes were thoroughly investigated by scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy, Raman spectroscopy, photoluminescence spectrum, X-ray diffraction, X-ray photoelectron spectroscopy, and N 2 adsorption–desorption measurement, thereby confirming the effect of Ni doping on H 2 S-sensing properties. The sensitivity to H 2 S gas of Ni-doped WO 3 flakes showed short response/recovery times of 17 s/110 s, high stability, good selectivity, and low operating temperature of 250 °C. Due to the increasing surface defects and oxygen vacancies with the presence of Ni 2+ ions in the structure of WO 3 flakes, the Ni-doped WO 3 sensor exhibited a better sensing of H 2 S gas than the pristine WO 3 sensor. This result indicates that the Ni-doped WO 3 flake structure is promising for detecting H 2 S gas as a selective, inexpensive, and outstanding sensor materials.