Porous thin sheet-based α-Fe₂O₃-doped In ₂O₃ structures: Hydrothermal synthesis and enhanced Cl₂ sensing performance

A facile hydrothermal route was employed to synthesize porous thin sheet-based α-Fe₂O₃-doped In₂O ₃ structures including nanosheets and microflowers without any surfactant and template. The morphologies of the porous thin sheet-based α-Fe₂O₃-doped In₂O₃ structures consisted of many porous thin sheets with lengths of 80-100 nm and widths of 5-10 nm, while the pores in the sheets were 2-10 nm, and the amount of α-Fe₂O₃-doping significantly affected the overall morphology. The characterization of the porous thin sheet-based α-Fe ₂O₃-doped In₂O₃ structures was obtained using nitrogen adsorption-desorption isotherms at 77 K. The results showed that the porous thin sheet-based α-Fe₂O ₃-doped In₂O₃ structures (S4) adsorbed the largest amount of N₂ and had the biggest surface area, which contributed to the improvement of the gas sensing characteristics. Furthermore, the gas sensing characteristics of the obtained products were studied. The results demonstrated that the sensors based on α-Fe₂O ₃-doped In₂O₃ structures exhibited a much higher response to Cl₂ than those without α-Fe ₂O₃ (S1), and the In/Fe = 9:1 (molar ratio) showed the highest response. The sensor based on porous thin sheet-based α-Fe ₂O₃-doped In₂O₃ structures (S4) exhibited a high response, up to 48.2 ± 4.8 to 5 ppm Cl₂, quick response-recovery behavior and excellent stability, which implies good potential for practical applications. Finally, the gas sensing mechanism was also studied.