Constructing a novel type-II + Z SrTiO₃/α-Bi₂O₃/β-Bi₂O₃ junction based on phase transition strategy for super-fast removal of antibiotics and H₂ evolution

Through a series of characterizations, the phase transition from α-Bi₂O₃ to β-Bi₂O₃ constructs a novel SrTiO₃/α-Bi₂O₃/β-Bi₂O₃-x heterojunctions. Such phase transition results in the removal efficiencies of levofloxacin and norfloxacin by the SrTiO₃/α-Bi₂O₃/β-Bi₂O₃-12 sample reaching 88 % and 94 % after 20 min of test. The first-order photoreaction rate constants attain 0.2 min⁻¹ and 0.16 min⁻¹. For these two antibiotics degradation, the photo-removal efficiency of total organic carbon is 80 % and 75 %, respectively. Five times of cycle tests reveal that the removal efficiencies of the levofloxacin and the norfloxacin maintain above 75 % and 84 %. Moreover, the SrTiO₃/α-Bi₂O₃/β-Bi₂O₃-12 sample also produces H₂ with rate constant of 3501 μmol/g/h. The excellent adsorption-photocatalysis activity comes from a large pore diameter of β-Bi₂O₃ and a type-II + Z energy band formation. Such energy band structure not only enhances the transfer and separation of the charge carriers, but also the conduction band electrons of SrTiO₃ and β-Bi₂O₃, the valence band holes of α-Bi₂O₃ are preserved to use in the photocatalysis. The Back Propagation neural network model achieves 97 % accurate calculation of removal efficiency and the regression function predicts the final removal efficiency under arbitrary conditions. The SrTiO₃/α-Bi₂O₃/β-Bi₂O₃-12 can be used to solve the water pollutant and energy source crisis.