Photocatalytic performance of PMN-PT@TiO₂highly enhanced by alternative spatial electric field induced charge separation effect

Efficient charge separation is a vital factor to gain high photocatalytic activity. Alternative spatial electric field generated by piezoelectric effect could significantly accelerate charge separation when introduced into photocatalyst system. In this work, famous piezoelectric lead magnesium niobate-lead titanate 0.675Pb(Mg_1/3Nb_2/3)O₃-0.325PbTiO₃(PMN-PT) was firstly constructed with TiO₂to prepare composite photocatalyst PMN-PT@TiO₂. The results indicate that the alternative spatial electric field, excited by ultrasonic wave vibration, greatly improves the photocatalytic degradation efficiency of rhodamine B (RhB) over PMN-PT@TiO₂by about 50%. The durability experiments suggest that PMN-PT@TiO₂can keep excellent photocatalytic stability even after several runs. Moreover, in the photocatalytic degradation of methylene blue (MB), the enhancement effect of alternative spatial electric field on photocatalytic performance is also observed. Importantly, this study provides a general method for constructing piezoelectric-based photocatalyst to capture solar energy, acoustic wave energy and wind energy, which will realize multi-field energy coupling and high photocatalysis.