Synthesis Of Carbon Dots And The Composites With Its Application In Photocatalysis

Carbon Dots are attracting more and more researchers since it have been discovered in 2004,due to the low cost of synthesis,excellent biocompatibility and low toxicity,chemical inertness and fluorescent properties similar to semiconductor quantum dots.Carbon dots as a multi-functional nano-materials are widely used in chemical sensing,biosensing,biological imaging,drug delivery,photodynamic therapy,photocatalysis and electrocatalysis and other fields.But there are also some problem for it,such as separation,purification,complex functionalization processes,lower quantum yield and uncertainty of geometry,composition and structure,these will have an impact on the practical application of carbon dots.This paper is mainly for carbon quantum dots in high-performance photocatalyst design,green synthesis routes and practical applications to provide more solutions.The main contents and results of this paper are as follows:1.We chose ascorbic acid as carbon precursor,hydrothermal synthesis,centrifugal separation and purification to obtain carbon quantum dots;Then we use carbon quantum dots,bismuth nitrate and sodium silicate as the main materials to synthesize BSO/CQDs composite photocatalyst by one pot hydrothermal route.The results show that the introduction of carbon quantum dots improves the photocatalytic activity of BSO nanosheets,when the CQDs is 2%wt in the system,BSO/CQDs have the optimal photocatalytic activity.The degradation efficiency of RhB was more than 96%after 90 min irradiation under simulated sunlight.2.We chose citric acid as carbon precursor,hydrothermal synthesis,dialysis separation and purification to obtain carbon quantum dots;Then we use bismuth nitrate and ammonium bicarbonate as the main materials to synthesize Bi2O2CO3 ultrathin sheets by hydrothermal method.BOC/CQDs composite photocatalysts were prepared by hydrothermal method using Bi2O2CO3 ultrathin sheets and carbon quantum dots as precursors.The results show that the introduction of carbon quantum dots improves the photocatalytic activity of Bi2O2CO3 ultrathin sheets,when the CQDs is 2%wt in the system,BOC/CQDs have the optimal photocatalytic activity.The degradation efficiency of RhB was more than 96%after 90 min irradiation under simulated sunlight.3.We chose ammonium citrate as carbon precursor,hydrothermal synthesis,dialysis separation and purification to obtain N doped carbon quantum dots;Then we use bismuth nitrate and N doped carbon quantum dots as the main materials to synthesize a-BO/N-CQDs composite photocatalysts by one pot hydrothermal route.The results show that the introduction of carbon quantum dots improves the photocatalytic activity of ?-Bi2O3 quantum tubes,when the N-CQDs is 2%wt in the system,?-BO/N-CQDs have the optimal photocatalytic activity.The degradation efficiency of RhB was more than 86%after 180 min irradiation under simulated sunlight.