Study On The Efficiency Of Carbon Nanotube Stabilized PDIs Photocatalysts For The Degradation Of Typical Pollutants In Water

Typical pollutants represented by PPCPs,dyes,etc.have caused serious water environment pollution in the past,and the typical pollutants circulating into water have led to serious issues and threatened human health.Perylene diimide and its derivatives（PDIs）nanophotocatalysts are promising photocatalysts for the degrdation of typical pollutants into harmless CO₂and H₂O for clean and efficient production.This work synthesized a series of high-performance nanophotocatalysts for amide and amino functionalized PDIs,and proposed the mechanisms and driving forces for carbon nanotube（CNT）stabilization to improve the environmental suitability of PDIs series materials.It revealed the supramolecular synthesis strategy and mechanism of in-plane polarization electric field induced by hydrogen bonding andπ-πstacking.Acid induction directs the formation of in-plane polarization electric field by influencing the local electrostatic distribution on the molecular surface of PDIs through self-assembly,which provides guidance and acceleration that can significantly improve the photoelectric separation efficiency of the material.Theπ-πstacking and hydrogen bonding networks build bridges for molecule-molecule transfer of photogenerated electron-hole pairs,providing a powerful aid to enhance the in-plane polarized electric field.The gelation process is an effective way to synthesize a series of PDIs functionalized with high electron affinity amino.The electron affinity confers excellent photocatalytic properties to PDIs making them ideal anionic radical precursors for PDIs.The high flexibility and freedom of the amino side chains help them to form clusters that provide significant strong electrophilic groups on the surface of the material.It also provide PDIs with unique SOMO orbitals,surface polarization electric fields and efficient electron transfer pathways for the continuous acquisition of electrons from Typical pollutants.The amide-and amino-functionalized PDIs achieved dramatically high degradation of diclofenac sodium（DCF）and methylene blue（MB）,in which the primary kinetic constants k reached 0.172 and 0.262 h^-1for the photocatalytic degradation of them by amide-functionalized PDIs,respectively,and k for the photocatalytic degradation of them by amino-functionalized PDIs was 0.923 and 0.351 h^-1,respectively.Despite the excellent photocatalytic performance of amide-and amino-functionalized PDIs nanophotocatalysts,however,their amide and amino side chain groups contain polar groups that may still lead to their solubilization,and the reusability,which compromised their environmental stability and applicability.In order to improve the stability of PDIs,this work successfully achieved the stabilization of PDIs photocatalysts by gas-phase self-assembly using CNT,and proposed a mechanism and synthesis method for stabilizing PDIs based on the limiting-effect of CNT.The stabilization process resulting from this limiting-effect synthesized PDIs with surface tubular and internal bamboo structures,allowing the stabilized PDIs nanophotocatalysts to approach toward the characteristics of CNT,significantly improving the photocatalytic performance of the materials.The limiting-effect also improves the transfer of photogenerated electron pairs,allowing electrons to transfer in three directions CNT-CNT,CNT-PDA and PDA-PDA with the help of three-dimensional hopping transfer phenomena.The k of photocatalytic degradation of DCF by PDIs nanophotocatalysts reached 1.106 h^-1after stabilization,and the material maintained efficient degradation of DCF after several cycles with strong environmental thermal stability.This work proposes a variety of novel supramolecular design strategies for the synthesis of PDIs nanophotocatalysts,and further significantly expands the environmental applicability of the PDIs series of materials,providing a new approach for water environmental management.