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 200–400 nm 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  > 420 nm) in the presence of H 2 O 2 . The amount of doped Cu, reaction time, initial pH, catalyst dosages and H 2 O 2 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 H 2 O 2 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 H 2 O 2 .