Self-Sacrificial Template-Driven LaFeO₃/α-Fe₂O₃ Porous Nano-Octahedrons for Acetone Sensing

Semiconducting metal oxides (SMOs) with a porous structure have been paid close attention because of their large specific surface area. Three-dimensional LaFeO3/α-Fe2O3 nano-octahedrons were synthesized by a facile one-step solvothermal method, and a metal–organic framework was used as a self-sacrificing template. The method included the synthesis of MIL-53(Fe)/Fe–La hydroxide precursor and its conversion into a LaFeO3/α-Fe2O3 porous nanostructure by thermal annealing in air. A variety of techniques were employed to study the structures and morphology of the nano-octahedrons, including XRD, field emission SEM (FESEM), TEM, XPS, ICP-OES, and BET analysis. The gas-sensing performances of LaFeO3/α-Fe2O3 nano-octahedrons to acetone were studied. Upon construction of a heterostructure, the gas-sensing performances of LaFeO3/α-Fe2O3 nano-octahedrons were significantly improved as compared to that of pure α-Fe2O3. In addition, the sensor was noted to have superior reversibility and selectivity. Such a good performance may be due to a porous nanostructure and p–n heterojunctions between two types of oxides.