Construction of p-n heterojunction film of Cu 2 O/α-Fe 2 O 3 for efficiently photoelectrocatalytic degradation of oxytetracycline.

A p-n heterojunction film of Cu ₂ O/α-Fe ₂ O ₃ was constructed by electrodepositing p-type Cu ₂ O microcubes on liquid phase deposited film of n-type α-Fe ₂ O ₃ . The surface morphology, the crystal phase and composition of Cu ₂ O/α-Fe ₂ O ₃ heterojunction film were characterized by scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The enhanced absorption in the visible light region was observed in UV-visible diffuse reflectance spectra. Meanwhile, an efficiently improved separation and faster transfer of photogenerated electrons and holes were revealed by photoluminescence spectra and electrochemical impedance spectra. The Cu ₂ O/α-Fe ₂ O ₃ p-n heterojunction was applied to photoelectrocatalytic degradation of oxytetracycline at a bias potential of +0.5 V under visible light illumination. After 60-min photoelectrocatalytic treatment, 73.3% of oxytetracycline was removed and the degradation rate constant reached 2.14 × 10 ^-2  min ^-1 . Moreover, the crystal phases and compositions for the used and fresh Cu ₂ O/α-Fe ₂ O ₃ films were studied, and a possible photoelectrocatalytic mechanism was proposed.
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