Preparation And Photocatalytic Properties Of Ti₃C₂-Based Composites

The rapid and efficient development model makes the country rise rapidly and people’s life has been greatly improved.At the same time,the pressure of rapid development on the environment and ecology has also attracted people’s attention.To advocate sustainable development and promote the harmonious coexistence between man and nature,we should pay close attention to development on the one hand and protect the environment on the other hand.In practicing the concept of sustainable development,China takes the lead.Green water and green mountains have achieved initial results,but the problem of pollution still has a long way to go.The progress of the times and science and technology has also provided a new attempt for environmental governance.China is a country with a large population.It has a large demand for water resources.At the same time,the amount of waste water produced is also huge,and it is very difficult to deal with.Especially,industrial wastewater is still difficult to solve efficiently and environmentally friendly in today’s science and technology is so developed.The emergence of photocatalytic technology makes it possible to treat organic wastewater with high efficiency and zero pollution.In this paper,Ti₃C₂was used as matrix to obtain more efficient composite photocatalyst by derivatization and semiconductor recombination,and the degradation performance and degradation mechanism of photocatalyst for organic pollutants were studied.It provides a certain reference for the application of composite photocatalyst based on mxene material in the field of photocatalysis.The research results are as follows:（1）Two dimensional（2D）layered material Ti₃C₂was prepared by etching method.Ti₃C₂/Bi₂WO₆composite was obtained by hydrothermal method with Bi（NO₃）₃·5H₂O and Na₂WO₄·2H₂O as raw materials.It was characterized by SEM,XRD,TEM,UV-Vis DRS and PL.The results show that the multi-layered Ti₃C₂in the composite is dispersed into a single layer and staggered with the flake Bi₂WO₆.The photocatalytic degradation effect of the composite material on AF is significantly higher than that of the pure phase Bi₂WO₆.When the content of Ti₃C₂in the composite photocatalyst is 7%,it shows good photocatalytic activity.After 60 min of degradation,the removal rate of AF from simulated organic wastewater can reach90.37%.Through the circulation experiment,it is found that after the catalyst is reused for 4 times,the removal rate of pollutants can still be maintained at 80.91%.It was found that h⁺and·O₂^-were the main active substances causing the degradation of AF.（2）Layered Ti₃C₂was prepared by etching method,and then three-dimensional（3D）flower ball Ti₃C₂/Ti O₂was formed by high-temperature calcination with Ti₃C₂as titanium source,and its performance was tested and analyzed.The results showed that Ti₃C₂/Ti O₂synthesized at 500℃had better degradation effect on AF.the degradation rate reached 97.57%and the reaction rate reached 6.5 times that of monomer after 90 min illumination.This is due to the high conductivity of Ti₃C₂and the Schottky barrier formed at the interface with Ti O₂,which helps the carrier transfer faster and reduces the possibility of its recombination;In addition,the flower ball shape shows its advantages,and the specific surface area is expanded several times,which is obviously superior to the light absorption of the material.It has good stability and can degrade AF by 86.39%after 6 experiments.It is found that h⁺and·O₂^-are the main active substances that Ti₃C₂/Ti O₂can degrade AF.（3）Granular Cd S was successfully synthesized by hydrothermal method with flower spherical Ti₃C₂/Ti O₂as carrier Cd S@Ti₃C₂/Ti O₂composite,and its properties and degradation effect on dye bright green（BG）were tested.The results show that when the load ratio of Cd S in the composite is 3:1,Cd S@Ti₃C₂/Ti O₂shows the best photocatalytic activity.Through the 60 min photo reaction experiment,the removal rate of BG can reach 94.38%.Through the cyclic experiment,it is found that the stability of the composite is good,and the degradation rate can reach 83.21%after 5times.Finally,it is found that electrons（e^-）and hydroxyl radical（·OH）are the main active substances that reduce the concentration of BG solution in the photocatalytic experiment.