Some oxide semiconductors with visible-light-driven photocatalysis such as Bi₂Fe₄O₉, CaBi₂O₄, Bi₆WO₁₂ become a hot topic. These oxides can be applied to the absorption of visible light for their relatively small bandgaps. Prof. XU Jinbao’s research group from Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences, explored the low-heating temperature solid state precursor method to synthesize Bi₂Fe₄O₉ submicron-rods. The diameter of Bi₂Fe₄O₉ submicron-rods is about 500-800 nm and the length of them is about 2-4 μm(Fig.1). 

 Researchers adopted precursor method to further calcine in low-heating temperature range from 600 to 800 °C to directly synthesize novel Bi₂Fe₄O₉ submicron-rods. It turns out that the Bi₂Fe₄O₉ submicron-rods attained at 700℃possess a perfect submicron-rod shape with a smaller bandgap (1.76 eV), which is smaller than the reported value of TiO₂ (3.2 eV)（Fig. 2）. Based on XRD and SEM result, the structure and morphology of the Bi₂Fe₄O₉ are closely related to reaction temperatures. Due to their good morphology and small bandgap, Bi₂Fe₄O₉ submicron-rods have the potential to be applied to visible-light-driven photocatalyst for environmental cleanup and optoelectric devices for solar energy conversion to electricity.

The work has been published on Journal of Alloys and Compounds (2013, 562, 64–68) and a related patent has been authorized (No.201110045937.7).

The related work was supported by the “Hundred Talents Project” Foundation and Western Light Talent Culture Project of CAS.

 

　 Fig.1 TEM and SEM micrographs of Bi₂Fe₄O₉ submicron-rods        

Fig.2 Calculated bandgap of Bi₂Fe₄O₉ with the tangent of the linear part as dotted line