Preparation Of Ta-based Perovskite And Photocatalytic Degradation Of Pollutants Performance Study

Semiconductor photocatalysis is attracting attention for its remarkable ability to convert clean solar energy into chemical fuels.Scholars have started to work on exploring and designing new photocatalysts to utilize visible light,which accounts for more than 40%of the solar spectrum,for pollutant degradation.Several metal oxides,metal sulfides,chalcogenide oxides,and carbon nitride polymer materials have also attracted the interest of scientists because of their good photovoltaic properties.So far,several promising photocatalysts have been developed,opening up new ways to utilize renewable energy sources.Among them,NaTaO3,a typical chalcogenide material with stable layered structure and excellent separation in charge separation,has attracted great interest as a catalyst for photocatalytic degradation.However,the wide band gap of NaTaO3,which can only utilize a very small fraction(about 2-3%)of the UV light from solar irradiation,limits the development and application of this class of materials.Therefore,NaTaO3 has been modified to improve its bandgap properties and thus its utilization of solar beams.So far,many strategies have been used to solve this problem,such as doping with metals,constructing defects,and fabricating heterojunctions,but the room for improvement is still huge.Therefore,it is important to explore suitable modification methods to construct an effective NaTaO3-based photocatalytic system for enhancing the photocatalytic performance.In this paper,the photocatalytic performance of NaTaO3 chalcogenide materials is improved by doping with metallic and nonmetallic elements and composite semiconductor construction as follows:(1)NaTaO3-type chalcocite was chosen as the catalyst to modulate the structure of the material of NaTaO3 by doping with A and B site elements(Fe,Ce,Ni,Mn,Bi)to induce the improvement of the performance,and to characterize and analyze its composition,structure and morphological features,and to study its degradation characteristics and mechanism of aqueous pollutants using alizarin red as the substrate.The effect of metal doping on the electron transport pathways of NaTaO3 was further investigated by electrochemical and optical tests,and the possible reaction mechanism in the photocatalytic degradation process was speculated.(2)Non-metallic N and S doped NaTaO3 composites with different ratios of thiourea were synthesized by hydrothermal method.The structure of the NaTaO3 materials was modulated by doping with O-site elements to induce the improvement of properties,and their composition,structure and morphological characteristics were characterized and analyzed.The effect of non-metallic N and S doping on the photocatalytic performance of NaTaO3 was explored by photocatalytic degradation of antibiotics,and the optimal doping amount of thiourea was determined experimentally.(3)The g-C3N4 material was prepared by a series of hydrothermal calcinations using cheap urea and melamine as raw materials.NaTaO3 was combined with g-C3N4 using the impregnation method to prepare highly efficient composite photocatalysts to improve the separation efficiency of electron-hole to enhance the utilization of visible light by the materials.The photocatalytic degradation performance of the composites was evaluated using the degradation process of rhodamine B and tetracycline hydrochloride.The composition,structure and morphology,electrochemical and optical tests were characterized and analyzed to investigate the possible mechanism to improve their catalytic performance.