Preparation And Photocatalytic Performance Of Polyaniline/Polymetallic Composites

The Cr(?)is one of the most toxic heavy metals.It is that great significance to effectively control the pollution of the Cr(?)in the environment.The semiconductor photocatalytic reduction of the Cr(?)is a green technology for the remediation of heavy metal pollution.The conjugated photoelectric polymers with semiconductor band structure have received much attention due to their good absorption performance of the visible light.Among them,the organic-inorganic photocatalytic materials,which are composed of p-type semiconductor polymer polyaniline(PANI)with cheap raw materials,easy synthesis and inorganic semiconductor,show high photocatalytic reduction activity of the Cr(?).In view of this,this paper focused on the composite modification methods of the PANI and Ag₂Mo O₄,Bi VO₄ and CuBi₂O₄ to regulate the photocatalytic materials,improve the spectral response range of organic-inorganic photocatalysts,promote the migration and separation efficiency of photogenerated carriers,and obtain a highly efficient photocatalyst for the catalytic reduction of the Cr(?).The main research contents and results are as follows:1.The p-n heterojunction PANI/Ag₂Mo O₄ composite photocatalytic materials were prepared by Cu²⁺catalyzed in-situ polymerization.It was found that the PANI and Ag₂Mo O₄ can form a well-matched p-n heterostructure,which can promote the photoelectrons transfer and photoelectron holes separation,and improve the photocatalytic activity.An appropriate amount of the Ag₂Mo O₄ is beneficial to the photoelectric charge transfer of the PANI/Ag₂Mo O₄ and the separation of photoelectric electrons from holes.The Cr(?)removal rate of the 10%PANI/Ag₂Mo O₄ was 97.5%.After 5 cycles,the Cr(?)removal rate remained 88.5%,showing excellent activity and stability of the Cr(?)photocatalytic reduction.2.The p-n heterojunction PANI/Bi VO₄composite photocatalytic materials were constructed by in-situ polymerization of aniline monomers on the surface of the Bi VO₄.The well-matched p-n heterostructure between PANI/Bi VO₄ can promote the photoelectrons transfer and the separation of photoelectrons and holes,and improve the photocatalytic activity.By adjusting the amount of the PANI polymerization on the Bi VO₄ surface,the optimal amount of the PANI polymerization can be obtained.The combination of appropriate amount of the PANI and Bi VO₄ is beneficial to the photogenerated electron transfer and separation of photocatalytic materials.The Cr(?)removal rate of the 25%PANI/Bi VO₄ was 98.3%,and the Cr(?)removal rate remained93.6%after 5 cycles,showing excellent visible light catalytic reduction ability and stability.3.The p-p heterojunction PANI/CuBi₂O₄ composite photocatalytic materials were constructed by in-situ polymerization with CuBi₂O₄ as the precursor.The p-p type heterojunction can accelerate the photogenerated electrons transfer and inhibit electrons-holes recombination,and the photocatalytic reduction of the Cr(?)is greatly improved.The combination of the CuBi₂O₄ precursor and appropriate amount of the PANI is more conducive to the photoelectric charge transfer and the separation of photoelectrons and holes in the composite photocatalytic materials.The25%PANI/CuBi₂O₄ had the highest visible light catalytic reduction activity of the Cr(?),and the Cr(?)removal rate reached 98.7%.After 5 cycles,the Cr(?)removal rate remained 92.5%,showing excellent stability and reproducibility.