Designing Bi2O3-Sn3O4 Z-scheme heterojunction on TiO2 NTs for improving photocatalytic performance

[Display omitted] •Bi2O3-Sn3O4 cosensitized TiO2 NTs were synthesized.•TiO2 NTs/Bi2O3-Sn3O4 showed the photocatalytic H2 generation rate of 58.75 μmol·cm−2·h−1.•TiO2 NTs/Bi2O3-Sn3O4 showed excellent photocatalytic performances toward MO/RhB/MB degradation and Cr(VI) removal.•The high photocatalytic performance is ascribed to the construction of Z-scheme heterojunction. The design of semiconductor heterostructures as the effective strategy are recognized to enhance the photocatalytic capacity of photocatalysts for the settlement of energy shortage and pollutant treatment. To efficiently utilize solar energy, the Bi2O3-Sn3O4 nanoparticles with the Z-scheme energy band structure were synthesized on TiO2 nanotube arrays (TiO2 NTs) by the solvothermal deposition method. The TiO2 NTs/Bi2O3-Sn3O4 exhibited the outstanding photocatalytic dye degradation and Cr(VI) removal, which was much higher than those of single Bi2O3 or Sn3O4 sensitized samples. The H2 evolution test indicated that the Bi2O3-Sn3O4 cosensitization dramatically enhanced the photocatalytic H2 generation ability of TiO2 NTs with the rate of 58.75 μmol·h−1·cm−2. The high photoelectric conversion was also confirmed, and the outstanding photocatalytic performance was further revealed by the contrast experiment. The plausible photocatalytic mechanism based on the ESR and capturing experiments indicated that the Z-scheme energy band structure induced the photoelectron separation and the generation of O2 and OH radicals, which was the decisive role for the improved photocatalytic performance.