Carbon-doped porous hollow alpha-Fe2O3 microtubules controlled by absorbent cotton bio-template to detect acetic acid vapor

Abstract

To overcome the scarcity and costliness of noble metal dopants, carbon (C) doping, as a low-cost alternative, was achieved by absorbent cotton when the alpha (α)-Fe2O3 microtubules were synthesized with a facile hydrothermal method and necessary calcination. The absorbent cotton not only provided carbon source but controlled the microtubular morphology of α-Fe2O3. Meanwhile, for comparison, a pure α-Fe2O3 nanoparticles sample was also prepared without using absorbent cotton. Numerous techniques were employed to characterize the element composition and microstructures. The consequences demonstrated that carbon had been successfully incorporated into the porous hollow α-Fe2O3 microtubules composed of many nanoparticles. Compared with the α-Fe2O3 nanoparticles, the carbon-doped α-Fe2O3 microtubules possessed the unique morphology, large specific surface area and pore size, and abundant oxygen vacancies (OV). To reveal the function of the carbon-doped α-Fe2O3 microtubules and α-Fe2O3 nanoparticles, two chemical gas sensors were manufactured and researched systematically. Forasmuch as those advantages mentioned above, the sensor based on the carbon-doped α-Fe2O3 microtubules exhibited better gas sensing properties to acetic acid vapor at a lower optimal operating temperature of 260 °C, such as higher response value, shorter response and recovery time, good repeatability, and stability. And thence the carbon-doped α-Fe2O3 microtubules product could be considered as an excellent acetic acid vapor sensor in the future. In addition, the possible grown mechanism and gas sensing mechanism of the carbon-doped α-Fe2O3 microtubules were discussed in detail. The work provides a new strategy to improve the gas sensing performance of α-Fe2O3 material.