Co-precipitation preparation and photocatalytic performances of BiNb5O14/Nb2O5 heterojunction

In the present study, BiNb5O14 and BiNb5O14/Nb2O5 heterojunction were prepared with co-precipitation synthesis. The crystal structure was studied via XRD patterns and Rietveld refinements, which has a typical tetragonal tungsten bronze (TTB)-type structure. The samples crystallized in micorods with a length of 1–4 µm and a diameter about 1 µm. As an indirect transition semiconductor, BiNb5O14 has a band energy of 2.81 eV with the valence-band formed by hybridized O-2p and Bi-6s, and the conduction band formed by Nb(6d) orbitals. The photocatalysis abilities of BiNb5O14 and BiNb5O14/Nb2O5 heterojunctions were evaluated via the photo-degradation of dye solutions. The photocatalytic activities were significantly improved via coupling BiNb5O14 with Nb2O5. In the photocatalysis reactions, •OH was the main reactive species, and the immigration rate of light-created charge-carriers was greatly improved via the heterojunction structure. The luminescence and decay lifetime were measured to discuss the photocatalysis mechanism.