Study On The Preparation Of Three New Photocatalysts And Their Applications On The Degradation Of Methylene Blue

Methylene blue（MB）is a typical poisonous pollutant which is extremely harmful to the ecological environment and human health.It is widespread in industrial and domestic sewage and photocatalysis is an effective method for the degradation of MB.This thesis mainly focuses on the preparation of three new kinds of photocatalysts.And the main results and conclusions are as follows:1.The TiO₂ catalyst derived from the high temperature oxidation of MXene（MDT）can effectively degrade MB under UV light.The MDT-800 catalyst,with high specific surface area and crystallinity,has the highest utilization rate of UV light and can degrade 98%of MB in 15 min.During the degradation process,its oxidation ability of photogenerated hole and the electron reduction ability of the catalyst are strong.Furthermore,the defects of the catalystcanprovidemorereactivesites.Thenalargenumberof strong-oxidation-ability·OH active groups were produced,which improve its photocatalytic activity.2.The TiO₂ modified catalyst loaded by MXene（MTx）,prepared by hydrothermal method,which can effectively degrade MB under UV light.Among them,the MT₁₆₀ catalyst with 44m² g^-1 of the specific surface area,has the lowest MXene content and the highest utilization rate of UV light and can degrade 97.5%of MB in 30 min.During the degradation process,MXene acts as conductor to transfer electrons from the conduction band of TiO₂,which can prolong the lifetime of photoinduced hole and generate a large number of strong-oxidation-ability·OH active groups,thus improving its photocatalytic activity.3.Three different kinds of copper benzyl acetylene photocatalysts were synthesized by three methods,which can degrade MB under visible light.The light synthesis method is more mild and safer than the heating method and the ultrasonic method.And copper benzyl acetylene photocatalyst prepared by light synthesis method（CP@L）has the highest utilization rate of visible light and can degrade 95%of MB just in 30 min,however,it has the smallest specific surface area.The results prove that the catalyst’s active crystal surface for the degradation of MB may be（001）,（010）,（110）crystal surfaces but not the（100）crystal surface.In the process of degradation,nanobelt structure of the CP@L is in favor of electron conduction and the active surface is exposed much,which results in strong-oxidation-ability·OH active groups and greatly improve its photocatalytic activity.