Application And Mechanism Of Strontium Titanate-based Piezoelectric Materials In The Degradation Of Carbamazepine

Carbamazepine（CBZ）is a common anti-epileptic and mood-stabilizing drug widely used in the treatment of psychiatric disorders.However,due to the widespread use and excessive discharge of CBZ,it has been detected in in environmental water bodies,which has seriously endangered the aquatic ecosystem.The essence of piezoelectric catalysis technology is the application of piezoelectric effect in chemical reaction,which refers to the phenomenon that the electric charge generated in the piezoelectric process directly participates in the chemical reaction.Strontium titanate（SrTiO₃）is a perovskite piezoelectric material with high dielectric constant,low dielectric loss,low preparation cost and high stability,and has been gradually paid attention to in the field of environmental management.However,the poor electrical conductivity,low crystal asymmetry,and wide band gap of SrTiO₃ are the limiting factors for its further development in the field of piezoelectric catalysis.Therefore,based on the above theoretical basis and the needs of environmental treatment,the following three parts of work have been carried out:1.The piezoelectric catalysts with different barium（Ba）elements replacing SrTiO₃at the A site were prepared,and the effect and mechanism of different Ba:Sr ratios on the performance of piezoelectric catalytic degradation of CBZ were explored.It was found that the degradation efficiency of Ba_0.5Sr_0.5Ti O₃ on CBZ reached 94.5%after 30min of ultrasonic vibration,which was much higher than that of pure SrTiO₃ and Ba Ti O₃.The physical mechanism is that the substitution of Ba enhances the asymmetry of the SrTiO₃ crystal,making it easier to deform to generate a stronger polarized electric field and piezoelectric effect,which in turn generates more reactive oxygen species（ROS）for degrading pollutants.In addition,electrochemical analysis shows that the polarized electric field generated by the piezoelectric effect enhances the transfer of carriers and reduces the resistance of the catalyst,thereby improving the piezoelectric response speed and the interface charge transfer speed.2.SrTiO₃ nanowires（STO-W）and SrTiO₃ nanoparticles（STO-P）were synthesized by hydrothermal method to explore the effect of morphology modulation on piezoelectric effect.Under the same experimental conditions,the first-order kinetic constant of STO-W during the degradation of CBZ is 0.0917 min^-1,which is 1.97 times that of STO-P.Piezoelectric current,UV-Vis DRS and EPR experiments show that STO-W has stronger conductivity and narrower bandgap.This is due to the higher aspect ratio of STO-W.Under the action of ultrasonic vibration,it can generate stronger deformation and strengthen the built-in electric field,promote the migration of charge carriers,and then strengthen the formation of ROS on its surface to remove CBZ.3.Construction of SrTiO₃/ZnO piezoelectric heterojunction to enhance the piezoelectric catalytic efficiency of SrTiO₃.The recombination of ZnO enhances the electrical conductivity of SrTiO₃,thereby realizing the rapid separation and transfer of piezoelectric charges.In addition,the formation of HO^·in the piezoelectric catalytic reaction system is regulated by the construction of the heterojunction.The energy band structure of the SrTiO₃/ZnO heterojunction is calculated,and the piezoelectric heterojunction is inferred to be"Z"type according to the EPR experimental results,and a reasonable oxidation degradation mechanism of pollutants is proposed.