Mechanistic Study on the Enhanced Generation of Surface Charges and Separation of Photogenerated Charges Induced by 001-Oriented NaNbO 3

The antibiotic residues in water have caused serious harm to the environment and living organisms with the development of pharmaceuticals. Therefore, it is crucial to study effective catalysts for degrading residual antibiotics. The piezoelectric catalyst of NaNbO3@BiFeO3 (NNO@BFO) composed of 001-oriented NaNbO3 (NNO) slices and BiFeO3 (BFO) particles was synthesized. The enhanced polarization of 001-oriented NNO boosted piezoelectric performances, which was helpful in promoting the migration of photogenerated charges and suppressing the recombination of electrons and holes. The electrons transferred from the conduction band (CB) of BFO to NNO through the p–n junction, and holes in the valence band (VB) transferred from that of NNO to BFO. •O2– was the main radical that eliminated OTC, and the dominant radicals in removing LEV were •OH and h+. The OTC and LEV were ultimately decomposed into inorganics through ring-opening, hydroxylation, bond breaking, and redox reactions within 120 min. The NNO@BFO-5 catalyst maintained a high degradation rate for OTC after 4 cycles, indicating its good stability and reusability. This work presented an effective piezoelectric photocatalyst, which enabled the degradation of antibiotics.