A hydrothermal approach is developed to fabricate Cu₂O film via in situ redox reaction between Cu²⁺ and Cu plate. The crystallization process under different conditions was demonstrated, and the crystal structure of Cu₂O was verified by XRD, Raman and XPS characterizations. Simply tuning the anionic groups of Cu²⁺ can generate different morphologies including rod-like arrays, cross-linked and truncated octahedrals. Mott–Schottky plots and PL spectra indicate that the rod-like arrays possess more copper vacancies than the other two morphologies. In photodegradation, the rod arrays exhibit much better performance, following by truncated and then cross-linked octahedrals. The photostability of the three morphologies was also determined. Although different surface reconstructions occur for the films owing to different charge transfer and consumption pathway, their photoactivities are all enhanced after the first run. Then rod arrays and cross-linked octahedrals show very stable activity, but truncated octahedrals show a gradually decreased activity. This work may be helpful for rationally modulating Cu₂O-based materials and understanding their deactive mechanism in photocatalysis. 

J. Phys. Chem. C