Synthesis of δ-Bi2O3/Bi2MoO6 composites with enhanced photocatalytic activity by hydrothermal method
Highlights: • The δ-Bi{sub 2}O{sub 3}/Bi{sub 2}MoO{sub 6} composites were first synthesized by hydrothermal method. • The product was δ-Bi{sub 2}O{sub 3} rather than α-Bi{sub 2}O{sub 3} with the preset of Bi{sub 2}MoO{sub 6}. • The composites show enhanced photocatalytic activity compared to Bi{sub 2}MoO{sub 6}, α- and δ-Bi{sub 2}O{sub 3}. • The excellent photocatalytic performance was attributed to δ- Bi{sub 2}O{sub 3}/Bi{sub 2}MoO{sub 6} heterojunctions. - Abstract: The δ-Bi{sub 2}O{sub 3}/Bi{sub 2}MoO{sub 6} composites were synthesized by hydrothermal method and the microstructure and photocatalytic property were characterized. The X-ray diffraction (XRD) analysis revealed that δ-Bi{sub 2}O{sub 3} was obtained with the existence of Bi{sub 2}MoO{sub 6}, while the product was α-Bi{sub 2}O{sub 3} without Bi{sub 2}MoO{sub 6} under the same experimental condition. The SEM images and the selected area electron diffraction (SAED) patterns have further verified that δ-Bi{sub 2}O{sub 3} was deposited on Bi{sub 2}MoO{sub 6}. The X-ray photoelectron spectroscopy (XPS) spectrum confirmed that the composites were composed of δ-Bi{sub 2}O{sub 3} and Bi{sub 2}MoO{sub 6}, while a fraction of Mo changed from Mo{sup 6+} to Mo{sup 5+}. The coexistence of Mo{sup 5+}/Mo{sup 6+} can be a critical factor in the formation of stable δ-Bi{sub 2}O{sub 3} on Bi{sub 2}MoO{sub 6}. Particularly, the δ-Bi{sub 2}O{sub 3}/Bi{sub 2}MoO{sub 6} photocatalysts possess favorable photocatalytic performance under simulated sunlight illumination since the recombination of photogenerated electrons and holes was inhibited due to the p-n junction at the interface of δ-Bi{sub 2}O{sub 3} and Bi{sub 2}MoO{sub 6}, and the mechanism was discussed in detail.