Flexo-catalytic Effect Of Perovskite Oxide Strontium Titanate

With the increasingly serious environmental pollution and energy shortage,the role of catalysis has become increasingly important.Catalytic technologies such as photocatalysis,piezoelectric catalysis,and pyroelectric catalysis have encountered different development bottlenecks after years of development,accompanied by endless solutions and exploration of new catalytic technologies.In this thesis,the hydrothermal and molten salt method were used to prepare strontium titanate（SrTiO₃）nanoparticles and microplates,respectively.In addition,low-crystallized strontium titanate（LC-Sr Ti O₃）nanoparticles and high-crystallized strontium titanate（HC-Sr Ti O₃）nanoparticles were prepared under different hydrothermal growth conditions.By exploring the catalytic degradation of colored dye solutions with different strontium titanate powders in a dark ultrasonic vibration environment,the flexo-electrical effect and electrochemistry are cross-coupled and we demonstrate a phenomenon of flexo-catalysis effect in centrosymmetric nanoparticles to degrade organic dyes via ultrasonic bubble cavitation as a stimulus.1.0 g/L high-crystallized strontium titanate nanoparticles（HC-STO）prepared by hydrothermal can catalytically degrade 91.9%rhodamine B solution whose concentration is10 mg/L within 10 hours under a dark environment with an ultrasonic power of 240 W.And1.0 g/L high-crystallized strontium titanate microplate（MP-STO）prepared by the molten salt method can catalytically degrade 93.6%rhodamine B solution within 6 hours.The results prove that ultrasonic bubble cavitation can stimulate the flexoelectric effect of strontium titanate in the solution,and the flexo-catalysis of the sheet-shaped strontium titanate material is stronger.Under a dark environment with an ultrasonic power of 240 W,1.0 g/L Mica powder obtained by ball milling mica flakes can catalytically degrade 90.6%rhodamine B solution within 10 hours,while 1.0 g/L Ti O₂ purchased from Aladdin can catalytically degrade 77.6%rhodamine B solution under the same experimental conditions.Experiments show that the flexo-catalysis can occur in any dielectric material,which greatly expands the choice of catalyst materials.Under a dark environment with an ultrasonic power of 240 W,1.0 g/L low-crystallized strontium titanate nanoparticles（LC-STO）prepared by hydrothermal in different conditions can catalytically degrade 92.2%rhodamine B solution within 4 hours.The experimental results prove that the presence of the amorphous phase of nanomaterials not only reduces the crystallinity of the material,but also greatly improves the flexo-catalytic performance.This finding not only suggests a new strategy to generate flexoelectric effect,but also opens up the possibility to extend existing catalytic techniques.