Large scale preparation of Cu-doped α-FeOOH nanoflowers and their photo-Fenton-like catalytic degradation of diclofenac sodium

Abstract

A facile reflux method was developed to prepare Cu-doped α-FeOOH (α-(Fe,Cu)OOH) nanoflowers consisted of nanorods with a length of 200–400nm in large scale. The obtained α-(Fe,Cu)OOH samples were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and UV–vis absorption spectra, and their catalytic performances were evaluated by the degradation of diclofenac sodium (DCF) in water under visible-light irradiation (λ>420nm) in the presence of H2O2. The amount of doped Cu, reaction time, initial pH, catalyst dosages and H2O2 dosages were investigated for their effects on the degradation efficiency of DCF, respectively. The results demonstrated that α-(Fe,Cu)OOH nanoflowers exhibited better catalytic performance in comparison with pure α-FeOOH, and the sample doped with 3% Cu (molar ratio of Cu to Fe) displayed the optimal visible-light photocatalytic activity. In addition, the degradation efficiency of DCF increased with the increasing of catalysts and H2O2 dosages, but decreased with the elevating of initial pH in the range of 5–8. The α-(Fe,Cu)OOH nanoflowers presented excellent stability with high degradation efficiency even after five cycles. The high catalytic activity of α-(Fe,Cu)OOH might be attributed to a special two-way Fenton-like, photo-catalytic mechanism and the synergistic activation of Fe and Cu in α-(Fe,Cu)OOH towards to H2O2.