Preparation And Photocatalytic Properties Of BiOI/KF-KYb₃F₁₀:Tm/MOF-5 Composites

With urbanization and industrialization,the massive use of fossil fuels has produced a variety of hard-to-degrade pollutants and other harmful substances,some of which are carcinogenic and teratogenic.At present,problems such as sea,air and soil pollution are becoming more and more serious.How to degrade these harmful substances becomes more and more important.Photocatalysis is an effective way to solve this problem,and researchers have been searching for efficient photocatalytic materials.In this paper,BiOI is compounded with MOF-5 and KF-KYb₃F₁₀:Tm to make new photocatalysts and and its photocatalytic performance was studied.The main research of this paper is as follows:The BiOI/MOF-5 and BiOI/KF-KYb₃F₁₀:Tm composites were firstly prepared by hydrothermal method.The effects of different composite ratios,different temperatures of the reaction,and different reaction times on their structures,morphologies and photoresponses were investigated.On this basis,BiOI/KF-KYb₃F₁₀:Tm/MOF-5composites were also prepared by hydrothermal method.The composites were characterized by XRD,SEM,TEM,FT-IR,BET,UV-Vis DRS,XPS and PL.The results showed that BiOI composite with MOF-5 and KF-KYb₃F₁₀:Tm did not change their respective structures significantly,but some interactions occurred between them.Meanwhile,BiOI/KF-KYb₃F₁₀:Tm/MOF-5,BiOI/KF-KYb₃F₁₀:Tm,BiOI/MOF-5composites have enhanced light absorption ability and broadened the light response range than BiOI,and BiOI/KF-KYb₃F₁₀:Tm/MOF-5 composites have higher light absorption ability than BiOI/KF-KYb₃F₁₀:Tm and BiOI/MOF-5.The photocatalytic performance of BiOI/KF-KYb₃F₁₀:Tm,BiOI/MOF-5 and BiOI/KF-KYb₃F₁₀:Tm/MOF-5 composites was tested,and the results showed that the degradation rates of methyl orange by BiOI/KF-KYb₃F₁₀:Tm and BiOI/MOF-5 under120 min visible light irradiation were 76.05%and 88.01%,respectively.The degradation rates of BiOI/KF-KYb₃F₁₀:Tm/MOF-5 composites were 98.81%for methyl orange under 100 min visible light irradiation.The stability and active substances of the photocatalysts were investigated by cycling and trapping experiments.It was shown that BiOI/KF-KYb₃F₁₀:Tm,BiOI/MOF-5 and BiOI/KF-KYb₃F₁₀:Tm/MOF-5 composites have good stability and efficient photocatalytic effect.The photocatalytic mechanism of BiOI/KF-KYb₃F10:Tm,BiOI/MOF-5 and BiOI/KF-KYb₃F10:Tm/MOF-5composites showed that superoxide radical（·O₂^-）played a leading role in the degradation of methyl orange,followed by·OH and h⁺.