Controllable Synthesis of Bi2Fe4O9 Nanocrystal with High Active Facets and the Enhanced Visible Light Photoelectrochemical Property

Bi 2 Fe 4 O 9 nanocrystals with high active facets were controllably synthesized via a chemical co-precipitation process followed by a hydrothermal treatment at various microenvironment. The nanocrystals can be controlled preferentially to grow along (001) and show flat side facets of (110) and (10). The photoinduced charge-transfer property of Bi 2 Fe 4 O 9 was significantly improved. Such a high photo-to-current conversion efficiency is ascribed to the synergistic effect of energy band structure and the high reactivity of exposed (110) and (10) facets. The high surface energy at the interface of the Bi 2 Fe 4 O 9 efficiently reduced the recombination of photoinduced electron-hole pairs, and thus increasing the lifetime of charge carriers and enhancing the photo-to-current efficiency of the Bi 2 Fe 4 O 9 .