The Mechano/thermo Catalysis Of Ferroelectric BaTiO₃ Nano Wires For Dye Wastewater Degradation

At present,a series of physical,chemical and biological methods have been developed and utilized to degrade harmful organic dye wastewater.Semiconductor photocatalysis,as a kind of green and environmental catalysis,has attracted wide attention and develops rapidly.However,due to the wide band gap of most semiconductor photocatalyst,its light absorption range is narrow and the degradation efficiency is low,which seriously hinders its application development.Therefore,it is urgent to develop an efficient and green dye wastewater degradation method.Nature vibrational energy and heat energy at room temperature transformation are other forms of clean energy is available to applications in organic dye wastewater treatment with broad application prospects.The piezoelectric effect of ferroelectric materials and pyroelectric effect can also have the vibration and at room temperature the ability to transform heat into electricity,and the conversion efficiency can be as high as 40%-60%and 45%respectively.Therefore,the degradation effect of mechanical and thermal catalysis induced by piezoelectric effect and pyroelectric effect is better than that of semiconductor photocatalysis.Therefore,we plan to study the degradation of dyes based on mechanical-electrochemical effects and thermo-electrochemical reactions.BaTiO3 nanowires is a typical lead-free ferroelectric material,with a relatively high piezoelectric coefficient(?45 pC/N)and pyroelectric coefficient(?90 ?Cm-2 K-1),and can be repeated bending,heating or cooling.It can be used as a catalyst to achieve an ideal mechanical and thermal catalysis.In this paper,we have achieved mechanical catalytic degradation based on mechanical-electrochemical effect based on the BaTiO3 nanowires synthesized by hydrothermal synthesis.With the help of low frequency ultrasonic vibration,the dye degradation rate can be as high as?98%in 60 minutes.In addition,under the excitation of cold-hot cycle,we achieved thermal catalytic dye degradation based on the thermal-electrochemical effect,and the degradation rate can be as high as?99%in 72 hot-cold cycles.To get a better catalytic effect,BaTiO3@ZnO nanomaterials were prepared by hydrothermal synthesis on the basis of BaTiO3 nanowires and dye degradation rate can be as high as?98%within 42 cold-hot cycles.In the repetitive experiments,catalyst still has very high dye degradation rates after repeated experiments,showing that the prepared catalyst can withstand long time vibration,or repeated heating and cooling.In addition,the active species such as hydroxyl and superoxide free radicals produced in the process of mechanical catalysis and thermal catalytic degradation were observed in the active species detection experiment.On the basis of experimental results,we discussed the mechanical catalysis and thermal catalysis.Results show that the lead-free ferroelectric BaTiO3 nanowires catalyst can be used in dye degradation application.