Hydrothermal synthesis and Cl2 sensing performance of porous-sheets-like In2O3 structures with phase transformation

Abstract

A facile hydrothermal route was employed to synthesize the porous-sheets-like In₂O₃ structures without any surfactant and template. The morphologies of the porous-sheets-like In₂O₃ structures consisted of many thin sheets with length of 40–120 nm, and the amount of Fe-doped significantly affected the overall morphologies and the phase transformation of In₂O₃. Furthermore, the formation mechanism of the porous-sheets-like In₂O₃ structure is investigated, which revealed that the doping of Fe plays a significant role in the self-assembled and oriented attachment mechanism of In₂O₃, and the phase transformation of In₂O₃ (the pure bcc-In₂O₃ was transformed into the pure rh-In₂O₃) also contributed to the formation of the porous-sheets-like In₂O₃ structure. Finally, the gas sensing characteristics of the products were studied. The results demonstrated that the sensor based on porous-sheets-like In₂O₃ structures (the coexistence of bcc-In₂O₃ and rh-In₂O₃) exhibited a much higher response (54.7 ± 5.3 for 5 ppm Cl₂) to Cl₂ than those pure bcc-In₂O₃ without Fe (S1) and pure rh-In₂O₃ (S5 and S6) samples, so the phase transformation influences on the gas sensing performance of In₂O₃. The porous-sheets-like In₂O₃ structures (S4) had the biggest surface area (42.5 m² g⁻¹), which contributed to the improvement of the gas sensing characteristics, the gas sensing mechanism were also studied.