Synthesis of δ-Bi 2 O 3 /Bi 2 MoO 6 composites with enhanced photocatalytic activity by hydrothermal method

Abstract The δ-Bi 2 O 3 /Bi 2 MoO 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 2 O 3 was obtained with the existence of Bi 2 MoO 6 , while the product was α-Bi 2 O 3 without Bi 2 MoO 6 under the same experimental condition. The SEM images and the selected area electron diffraction (SAED) patterns have further verified that δ-Bi 2 O 3 was deposited on Bi 2 MoO 6 . The X-ray photoelectron spectroscopy (XPS) spectrum confirmed that the composites were composed of δ-Bi 2 O 3 and Bi 2 MoO 6 , while a fraction of Mo changed from Mo 6+ to Mo 5+ . The coexistence of Mo 5+ /Mo 6+ can be a critical factor in the formation of stable δ-Bi 2 O 3 on Bi 2 MoO 6 . Particularly, the δ-Bi 2 O 3 /Bi 2 MoO 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 2 O 3 and Bi 2 MoO 6 , and the mechanism was discussed in detail.