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

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 Cl-2) to Cl-2 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 m(2) g(-1)), which contributed to the improvement of the gas sensing characteristics, the gas sensing mechanism were also studied.