Enhanced Photocatalytic and Fenton-like Performance of CuOx-Decorated ZnFe₂O₄

A series of CuO x -decorated ZnFe 2 O 4 samples were prepared by a hydrothermal method and investigated as a catalyst for the photocatalytic and Fenton-like degradation of Orange II. The active species and catalyst active sites in the two processes were also studied. It was found that the introduced CuO x significantly enhanced the photocatalytic and Fenton-like performance of ZnFe 2 O 4 . Especially, ZnFe 2 O 4 –Cu3 prepared with the Cu/Zn ratio of 3:7 exhibited a very high Fenton-like activity in the pH range 5–9. The enhanced photocatalytic activity of ZnFe 2 O 4 –Cu3 could be because the formed ZnFe 2 O 4 /Cu 2 O heterojunction improved the separation efficiency of the photogenerated carriers. The photogenerated hole was responsible for Orange II degradation. As for the Fenton-like reaction, • O 2 – was the active species, and the surface ≡Cu 2+ with a higher redox ability should be the active site for H 2 O 2 activation despite its lower surface content than that of ≡Cu +, ≡Fe 2+, and ≡Fe 3+ . Finally, a possible pathway for Orange II degradation was proposed according to the liquid chromatography–mass spectrometry result.