Construction of p-n heterojunction film of Cu2O/α-Fe2O3 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.