Investigation On The Enhanced Photocatalytic Activity Of Nanodot-modified Photocatalyst

In this paper,a three-dimensional structure of flower-like microspheres Bi₂O₂CO₃ was used as the body material,and then a series of composite photocatalysts have been prepared via nano particles modification.And the relationship between the composition,structure and performance of photocatalysts have been tested and studied.The new methods for enhancing the degradation activity and raising the utilization ratio of visible light via nano point regulation three-dimensional structure have been established,and the mechanism of visible light absorption and charge separation,which is revealed that it's helpful for promoting the photocatalytic performance.In addition,MIL-53(Fe)materials are development studied as body materials.Bi₂O₂CO₃ with three-dimensional flower-like microsphere structure was prepared by hydrothermal method,and then the surface of Bi₂O₂CO₃ was modified by the Cu₂O NPs(?10 nm)via in-situ synthesis method.The results showed that the degradation rates of MB and phenol by using Cu₂O/Bi₂O₂CO₃ were as high as 94.0%and 50.8%,respectively,within 20 min.The research provides a simple and effective technology for the degradation of organic wastewater under visible light.Bi₂O₂CO₃ was modified by Ag@Ag Cl NPs(?20 nm)and Ag@Ag Br NPs(?20nm)via oil-water self-assembly/photoreduction method,respectively.The degradation rates by Ag@Ag Cl/Bi₂O₂CO₃ and Ag@Ag Br/Bi₂O₂CO₃ were 97.9%and 95.2%for MB,and 50.7%and 54.9%for BPA,respectively,within 20 min.The research proposes a new theory that surface plasmon effect regulates visible light absorption of three-dimensional photocatalytic materials and reveals the essence of surface plasmon effect enhancing visible light energy conversion efficiency of three-dimensional spherical compounds.Homogeneous carbon quantum dots(CQDs)solution was prepared by electrolysis method.The CQDs(?2-5 nm)was uniformly dispersed on the surface of Bi₂O₂CO₃ by dynamic adsorption precipitation method.The degradation efficiency of CQDs/Bi₂O₂CO₃ in visible light within 2 h was up to 94.5%for MB,the removal rate of total organic carbon(TOC)was up to 80.6%,and the degradation rate of phenol was up to 62.0%.Subsequently,Ag NPs and CQDs were simultaneously modified on the surface of Bi₂O₂CO₃.The degradation rate of Ag/CQDs/Bi₂O₂CO₃ for MB and BPA was up to 93.9%and 54.9%respectively within 90 min under visible light irradiation.In addition,the degradation rates of Ag/CQDs/Bi₂O₂CO₃ were 73.8 and99.3%for MB respectively under ultraviolet light and simulated sunlight.This study proposes the theory of up-conversion and surface plasma effect synergistically using full spectrum sunlight to improve photocatalytic efficiency,establishing a new method that nanometer point(or quantum dots)enhanced the photocatalytic activity of three-dimensional flower-like micro/nano structure materials,developing a new material system for photocatalytic degradation using full spectrum sunlight.On the basis of the above studies,MIL-53(Fe)was used as the body materials,and Ag NPs(?15 nm)and CQDs(?5 nm)were successfully modified on the surface of MIL-53(Fe)rod structure.The degradation efficiency of Ag/CQDs/MIL-53(Fe)in simulated sunlight within 2 h was up to 93.1%for MB,and the degradation activity in ultraviolet light,visible light and infrared light was up to 75.8%,76.4%and 41.5%,respectively.In this study,the mechanism of synergistic use full-spectrum sunlight to improve photocatalytic degradation efficiency among SPR effect,up-conversion effect and LMCT effect was explored,and the charge transfer process was described in detail.