Heterostructured ZnO/Fe2O3 nanograins-based sensors for formaldehyde detection

Heterostructured ZnO/Fe2O3 nanofibers were prepared by electrospinning method with the precursors Polyvinyl alcohol, zinc acetate dihydrate and iron (II) chloride anhydrous salts. Through the scanning electron microscopy characterization studies, uniform distribution of nanofibers was observed. These nanofibers were calcinated at 450 degrees C for 12 h to obtain polycrystalline ZnO/Fe2O3 with average grain diameter of 21 nm. The calcinated ZnO/Fe2O3 nanograins exhibited polycrystalline nature, which is confirmed by the X-ray diffraction pattern. X-ray photoelectron spectroscopy studies confirmed the presence of Zn and Fe in the synthesized ZnO/Fe2O3 nanograins. The prepared heterostructure ZnO/Fe2O3 nanograins showed a good response to 20 ppm of formaldehyde at an operating temperature of 300 degrees C. ZnO/Fe2O3 nanograins exhibited a quick response (17 s) and recovery (11 s) towards 20 ppm of formaldehyde. The formaldehyde vapour sensing mechanism was proposed based on the electron transport between ZnO/Fe2O3 nanograins at 300 degrees C.

Automated summary

Heterostructured ZnO/Fe2O3 nanofibers were prepared using electrospinning method. The resulting nanofibers showed uniform distribution and were calcinated at 450 degrees C to obtain polycrystalline ZnO/Fe2O3 with an average grain diameter of 21 nm. The X-ray diffraction and X-ray photoelectron spectroscopy studies confirmed the composition and nature of the nanograins. The prepared ZnO/Fe2O3 nanograins exhibited a quick response and recovery towards formaldehyde vapor.