Effect of organic solvents on iron oxide nanoparticles by solvothermal method

Soamwadee Chaianansutcharit^a,*, Okorn Mekasuwandumrong^b and Piyasarn Praserthdam^c

^a Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.

^b Department of Chemical Engineering, Faculty of Engineering and Industrial Technology, Silapakorn University, Nakornpatom 73000, Thailand.

^c Center of Excellence on Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand

Abstract— Single crystal g-iron oxide, maghemite, nanoparticles were successfully synthesized by solvothermal method using iron (III) acetylacetonate alone in 1,4-butanediol and in toluene at temperature of 250-300^oC. Phase identification, crystal size analysis and morphology were performed using X-ray powder diffractometry (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM), respectively. When influences of reaction temperature, time, and concentration of iron (III) acetylacetonate were studied, the distinction of crystal size particles in both solvents was resulted, suggesting the differences in crystallization pathway of maghemite in 1,4-butanediol and in toluene. In 1,4-butanediol, maghemite was proposed to crystallize and precipitate from glycoxide while those in toluene crystallized from amorphous phase via a solid-state reaction. The calcination of products at 350oC indicated that maghemite prepared in 1,4-butanediol has higher thermal stability than those prepared in toluene, which easily transformed to a-Fe₂O₃, hematite.

Keywords— nanoparticles; solvothermal method; crystallization pathways