Study On Photocatalytic Performance Of Nano-Ag₃PO₄

Semiconductor photocatalysis has potential application in the fields of energy and environmental protection because of its mild reaction conditions and the ability to directly convert solar energy into chemical energy.The most widely studied semiconductor photocatalysis is the wide bandgap semiconductors,such as TiO₂,ZnO,and the responsive spectrum is the ultraviolet part of the solar spectrum（the solar spectrum accounts for 5%）.Therefore,looking for semiconductor materials with visible light response（44%of solar spectrum）,researching ways and physical mechanisms to improve the utilization efficiency of solar energy,has important scientific significance and practicality for expanding the application range of semiconductor materials and effectively utilizing solar energy value.Silver phosphate is a visible light catalyzed material that has attracted attention in recent years.Our previous research work has prepared silver phosphate microcrystals.Photocatalytic degradation of dyes has shown that the photocatalytic efficiency of silver phosphate depends on its size.Therefore,how to prepare nano-silver phosphate and further improve its photocatalytic efficiency is the main research content of this thesis.In this paper,silver phosphate nanoparticles were prepared by ion exchange synthesis method by controlling the nucleation rate of nano-silver phosphate.The photocatalytic properties and material stability of different nanometer sizes were studied using a simulated solar device.The specific research contents are as follows:（1）Nanoparticles with a particle size of less than 20 nm were synthesized by liquid phase ion exchange method with the assisted of sodium citrate while using silver nitrate and trisodium phosphate as raw materials.A series of Ag₃PO₄nanoparticles with gradually changing sizes were synthesized by changing the reaction time.The structure,morphology and optical properties of the prepared samples were investigated.（2）Three representative dyes were selected:methyl orange（MO）,methylene blue（MB）and rhodamine B（RhB）for photocatalytic degradation testing.The photocatalytic properties and recyclability of materials of different sizes were investigated.The research results obtained are:（1）As the reaction time increases,the size of Ag₃PO₄ nanoparticles increases gradually.When the reaction time is 10 min,nanoparticles with particle size less than20 nm can be obtained.（2）The Ag₃PO₄ sample with a size of less than 20 nm has excellent catalytic performance and can completely catalyze MB in 10 min.And with respect to anionic dyes such as methyl orange,the Ag₃PO₄ photocatalyst can more effectively remove cationic dyes such as methylene blue and rhodamine B.（3）Analytical characterization of nano-Ag₃PO₄ before and after photocatalytic reaction,the results show that the prepared samples have good stability and reusability.