Structure Analysis of Fe₃O₄@SiO₂ Core Shells Prepared from Amorphous and Crystalline SiO₂ Particles

This article reports the results synthesis of crystalline (Fe₃O₄@c-SiO₂) and amorphous (Fe₃O₄@a-SiO₂) nanoparticles from natural resources (iron sand and silica sand). The synthesis of Fe₃O₄ and SiO₂ nanoparticles used co-precipitation and hydrothermal-coprecipitation methods with polyethylene glycol (PEG) 4000 as a template. The XRD data analysis presented that the amorphous SiO₂ particles were successfully produced using hydrothermal and co-precipitation methods. The XRD data analysis also presented that the crystalline phases were formed in quartz and tridymite phases after calcination process of the amorphous phase. SEM images exhibited that the amorphous phase had different particle size and morphology from the crystalline phase. FTIR spectra presented some absorption peaks of new functional groups indicating the existence of Si-O-Si (silanol), Fe-O, C-N, and Fe-O-Si as new functional groups.