ZnFe2O4 tubes: Synthesis and application to gas sensors with high sensitivity and low-energy consumption

ZnFe₂O₄ tubes with mesoscale dimensions were synthesized by pyrolysis of polyvinyl alcohol (PVA)-mediated xerogel using porous alumina as a template. The product formation was analyzed by X-ray powder diffraction (XRD), Fourier transformation infrared spectroscopy (FT-IR), thermogravimetry and differential thermal analysis (TG–DTA), scanning electronic microscopy (SEM), transmission electron microscopy (TEM) and high-resolution TEM (HRTEM). This synthetic method yielded open-ended ZnFe₂O₄ tubes with a typical length of several micrometers, an outer diameter of about 200 nm, and an average thin wall of 20 nm composed of small nanocrystals. Application of the ZnFe₂O₄ tubes as gas sensor materials displayed low-energy consumption and high sensitivity to organics such as ethanol and acetone, due to the unique interconnected channel structure and small crystal size of the tubes, showing their potential application in sensor areas.