Acetone sensors based on microsheet-assembled hierarchical Fe₂O₃ with different Fe³⁺ concentrations

Abstract

Several different morphologies of microsheet-assembled Fe₂O₃ have been fabricated by hydrothermal method using diverse concentrations of Fe³⁺ precursor solutions (0.025, 0.020, 0.015, 0.010 mol/L Fe³⁺). The as-synthesized materials have been characterized by scanning electron microscope (SEM), X-ray powder diffraction (XRD), and energy-dispersive X-ray spectrometry (EDS). The SEM images reflect that the morphologies of as-synthesized materials are affected by the concentrations of Fe³⁺ in precursor solutions. The less concentration of Fe³⁺, the more porous of Fe₂O₃ microflowers, and thinner of slices distributed on the surface. Furthermore, gas sensors based on these Fe₂O₃ microflowers manufactured and tested to various common gases. The optimum response value to 100 ppm acetone is 52 at the working temperature of 220 °C. Meanwhile, the Fe₂O₃ microflower sensors possess ultrafast response-recovery speed, which are 8 and 19 s, respectively. The possible sensing mechanism was mainly attributed to the high surface area, three-dimensional porous structure.