Glucose-assisted synthesis of mesoporous maghemite nanoparticles with enhanced gas sensing properties

Spindle-like mesoporous maghemite nanoparticles (MMNs) have been fabricated via a glucose-assisted hydrothermal and calcination process by using β-FeOOH nano-spindles as the precursor. The phase purity, morphology, structure and surface area of MMNs were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, high-resolution transmission electron microscopy and Brunauer-Emmett-Teller analysis. The results demonstrated that MMNs preserved a good individual dispersion and had a uniform morphology of about 150 nm in length and 50 nm in width. These nanoparticles were used as gas sensors and exhibited high responses for many reducing gases, including ethanol, acetone, ethyl acetate, benzene, etc. Specifically, the gas response (Ra/Rg) of MMNs to 1000 ppm acetone was about 217. Moreover, the MMNs-based sensor also showed a good selectivity and long-term stability under various ambient environments. The superior gas sensing properties of MMNs may be due to their large surface area (86.9 m2 g−1) and special crystal structure.