title: Preparation of magnetic recoverable nanosize Cu-Fe2O3/Fe photocatalysts.
abstract: Iron based catalysts generally have the advantage of the easily operated magnetically recovery from application sites. In the present work, paramagnetic iron and copper core-shell nanoparticles having the iron fractions (X(Fe) = Fe/(Cu+Fe)) of 0.33-1.0 were prepared and characterized by in situ synchrotron X-ray absorption and scattering spectroscopy. During the temperature-programmed carbonization (TPC) of Cu(2+)- and Fe(3+)-β-cyclodextrin (CD) complexes, a rapid reduction of Cu(II) occurs at about 453 K together with a growth of the metallic copper (Cu). Iron proceeds in the distinct growth path. At 453-513 K, the Fe(III) → Fe(II) → Fe consecutive reduction is observed. The unreduced Fe(III) (7-13%) is coated on the surfaces of the Fe nanoparticles (as Fe2O3/Fe). Growth of the Fe nanoparticle is inhibited by the surface Fe2O3, while the steady growth in Cu is observed. The Cu has a size range of 14-18 nm in diameter, compared to the small Fe2O3/Fe ones (3-6 nm). Under the UV-visible light irradiation for four hours, methylene blue can be photocatalytically degraded (>90%) by the (Cu-Fe2O3/Fe)@C. The (Cu-Fe2O3/Fe)@C photocatalysts can effectively oxidize dye molecules, providing a promising alternative for dye degradation using solar energy. Recovery of the (Cu-Fe2O3/Fe)@C photocatalysts can be attained by applying external magnetic field to trap the ferromagnetic Cu-Fe2O3/Fe nanoparticles, which suggests an economically attractive process, especially applied in photocatalytic degradation of dye-contaminated wastewater.
authors.affiliation: Department of Environmental Engineering, National Cheng Kung University, Tainan 701, Taiwan.
authors.forename: Hsu-Ya
authors.initials: HY
authors.lastname: Kang
authors.forename: H Paul
authors.initials: HP
authors.lastname: Wang
mesh_terms: D002384:Catalysis; D004396:Coloring Agents / Q000737:chemistry; D003300:Copper / Q000737:chemistry* / Q000528:radiation effects; D005290:Ferric Compounds / Q000737:chemistry* / Q000528:radiation effects; D007501:Iron / Q000737:chemistry* / Q000528:radiation effects; D060328:Magnetic Phenomena; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure; D008751:Methylene Blue / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D010782:Photolysis; D014466:Ultraviolet Rays
chemical_list: D004396:Coloring Agents; D005290:Ferric Compounds; C000499:ferric oxide; D003300:Copper; D007501:Iron; D008751:Methylene Blue