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.

Morphology-tunable ultrafine metal oxide nanostructures uniformly grown on graphene and their applications in the photo-Fenton system

“…The high photo-Fenton activity and high stability of the as-synthesized samples may be attributed to the synergistic coupling effects in these samples: (1) the unique morphologies of 0D QDs (ca. 36 To elucidate the mechanism involved in the photo-Fenton degradation of organic contaminant, trapping experiments for both • OH and O 2 •− have been conducted in this work to determine the specific reactive species that played a major Fig. 31,37 (2) 2D graphene sheets could be regarded as ideal conductive substrates, which may improve the electron transport.…”

Cu-Doped Extremely Small Iron Oxide Nanoparticles with Large Longitudinal Relaxivity: One-Pot Synthesis and in Vivo Targeted Molecular Imaging

“…8−10 The use of Cu as a dopant, alone or in combination with other metals, in iron oxide nanoparticles, is limited, compared, for example, to its use as a dopant in ZnO nanoparticles. Cu doping effect has been studied in catalysis, 11 sensor performance, 12,13 and in the magnetic properties of the nanomaterial. 14−16 The use of Cu as a dopant for molecular imaging is limited, with one example, in combination with Co, using nanorods for MRI 17 and one example where the 64 Cu radioisotope is used for positron emission tomography.…”

In situ X-ray absorption spectroscopic studies of photocatalytic oxidation of As(III) to less toxic As(V) by TiO2 nanotubes

“…However, carcinogenic by-products such as halogenated hydrocarbons in those chemical oxidation processes may be formed (Lata & Samadder, 2016). Molecular-scale data such as coordination number (CN), bond distance and oxidation state of select elements in a complicated matrix can be determined by X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) spectroscopy (Kang & Wang, 2013;Huang et al, 2003;Lin & Wang, 2000;Liu & Wang, 2004). By EXAFS, in the previous studies, we found that copper oxide clusters are involved in catalytic decomposition of NO and oxidization of chlorophenols (in supercritical water) .…”