Highly Efficient Visible Light Photocatalytic Activities in Self‐Assembled Metastable TiO2/Bi4MoO9 Heterojunctions

Abstract Metastable TiO 2 /Bi 4 MoO 9 heterojunctions are synthesized using a hydrothermal method. TiO 2 nanoparticles, which are used as templates in the hydrothermal process, can induce the heterogeneous nucleation and 1D preferential growth of Bi 4 MoO 9 to form TiO 2 /Bi 4 MoO 9 heterojunctions. The TiO 2 /Bi 4 MoO 9 heterojunctions exhibit very efficient visible‐light photocatalytic activity, which is much higher than those of TiO 2 nanoparticles, Bi 4 MoO 9 microcubes, and TiO 2 /Bi 2 MoO 6 composites. This could be mainly ascribed to the synergistic effects of the band structure matching and the unique microstructure between TiO 2 nanoparticles and Bi 4 MoO 9 nanobelts in the heterojunctions. The Bi 4 MoO 9 nanobelts with ≈150 nm in width promote the production of photogenerated electron–hole pairs due to its narrow bandgap. The TiO 2 nanoparticles embedded into Bi 4 MoO 9 nanobelts still remain small size, large specific surface area, and high crystallinity. These not only facilitate the transfer of photogenerated holes from Bi 4 MoO 9 nanobelts to TiO 2 nanoparticles, but also improve the holes capture rate on the surface of the heterojunctions.