Solvothermal in situ synthesis of Fe3O4-multi-walled carbon nanotubes with enhanced heterogeneous Fenton-like activity

Fe3O4-multi-walled carbon nanotubes (Fe3O4-MWCNTs) hybrid materials were synthesized by a solvothermal process using acid treated MWCNTs and iron acetylacetonate in a mixed solution of ethylene glycol and ultrapure water. The materials were characterized using X-ray powder diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, and vibrating sample magnetometry. The results showed that a small amount of water in the synthesis system played a role in controlling crystal phase formation, size of Fe3O4, and the homogeneous distribution of the Fe3O4 nanoparticles deposited on the MWCNTs. The Fe3O4 nanoparticles had diameters in the range of 4.2–10.0 nm. They displayed good superparamagnetism at room temperature and their magnetization was influenced by the reaction conditions. They were used as a Fenton-like catalyst to decompose Acid Orange II and displayed a higher activity than nanometer-size Fe3O4.

Graphical abstractAfter purification, the multi-wall carbon nanotubes (MWCNTs) act as seeds for Fe3O4 nanoparticles heterogeneous nucleation. The Fe3O4 nanoparticles with diameter range of 4.2–10.0 nm synthesized in situ on the MWCNTs under solvothermal condition. The formed nano Fe3O4-MWCNTs decolorized the Acid Orange II effectively via Fenton-like reaction.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The amount of water tunes size and size distribution of the Fe3O4 nanoparticles (FNs). ► FNs are homogeneously coated on the multi-walled carbon nanotubes (MWCNTs). ► FNs have diameters in the range of 4.2–10.0 nm, average grain size of 7.4 nm. ► Fe3O4-MWCNTs are used as a Fenton-like catalyst to decompose Acid Orange II. ► Fe3O4-MWCNTs displayed a higher activity than nanometer-size Fe3O4.