One-step aromatic acids assisted synthesis of γ-Fe2O3 nanoparticles with large surface area by thermal decomposition of ferric nitrate

Maghemite (gamma-Fe2O3) has attracted much attention due to its variety of applications in many areas. However, the current preparation methods of gamma-Fe2O3 still involve complicated processes and a high cost, thereby needing improvement. In this study, a novel and facile one-step solid-state method for the preparation of gamma-Fe2O3 nanoparticles (NPs) is performed through the thermal decomposition of ferric nitrate (Fe(NO3)(3)center dot 9H(2)O) and the addition of aromatic acids. Three aromatic acids that have different numbers of carboxyl groups (i.e., benzoic acid, phthalic acid, and trimesic acid) are used as additives and their effects on the formation of gamma-Fe2O3 NPs are investigated. Furthermore, the influence of the aromatic acid/Fe(NO3)(3)center dot 9H(2)O mass ratio and calcination temperature on the structural properties of the products are investigated. The structural properties, morphology, and magnetic properties of the products are analyzed through X-ray diffraction, transmission electron microscopy, scanning electron microscopy, nitrogen adsorption/desorption measurements, and magnetic measurements. The results show that the addition of aromatic acids to Fe(NO3)(3)center dot 9H(2)O leads to the formation of gamma-Fe2O3 NPs, and has a significant influence on the morphology of gamma-Fe2O3 NPs. When the aromatic acid/Fe(NO3)(3)center dot 9H(2)O mass ratio is greater than 0.5, the addition of the three aromatic acids leads to the formation of pure gamma-Fe2O3. The gamma-Fe2O3 NPs obtained from benzoic acid/Fe(NO3)(3)center dot 9H(2)O and phthalic acid/Fe(NO3)(3)center dot 9H(2)O systems do not show a welldefined morphology. In contrast, the gamma-Fe2O3 NPs obtained from the trimesic acid/Fe(NO3)(3)center dot 9H(2)O system are composed of a porous three-dimensional hierarchical structure and have the largest Brunauer-Emmett-Teller surface area (100.0 m(2) g(-1)).

Automated summary

In this study, a novel and facile one-step solid-state method for the preparation of gamma-Fe2O3 nanoparticles (NPs) was developed. The addition of aromatic acids to Fe(NO3)(3)•9H(2)O led to the formation of gamma-Fe2O3 NPs and significantly influenced their morphology. The gamma-Fe2O3 NPs obtained from the trimesic acid/Fe(NO3)(3)•9H(2)O system exhibited a porous three-dimensional hierarchical structure and the largest Brunauer-Emmett-Teller surface area.