Preparation And Photothermal Conversion Properties Of Co Based Nanomaterials

With the development of the economy,the global demand and consumption for energy are gradually increasing.Solving the problem of energy demand is a major challenge facing the world.The energy on the earth mainly comes from solar energy.Efficient utilization and conversion of solar energy is an effective way to solve the energy problems.Currently,the methods of converting solar energy include photothermal,photoelectric and photochemical conversion.Compared with other methods,converting solar energy into thermal energy is the simplest way of utilization,and the available materials are abundant.The photothermal conversion efficiency is an important parameter for materials to convert light-energy into heat-energy.However,most of the synthesized photothermal conversion materials have some drawbacks,such as poor photostability and low photothermal conversion efficiency.Therefore,it is of great significance to prepare photothermal conversion materials with high photothermal conversion efficiency for solar-driven water evaporation and tumor treatment.Cobalt hydroxystannate(CoSn(OH)₆)has a perovskite structure.CoSn(OH)₆ has the advantages of simple preparation method,strong adsorption capacity and catalytic activity,making it have a wide range of application prospects in supercapacitor,catalysis,electrochemical sensing and so on.However,its wide band gap and low optical absorption limit its application in photothermal conversion.Therefore,based on CoSn(OH)₆,Co based nanomaterials were constructed for solar-driven interface water evaporation and combined photothermal/photodynamic/enzymatic therapy of tumors.The main contents of the research are as follows:(1)Co-Sn alloy was prepared by H₂ reduction method using CoSn(OH)₆ as the raw material.It has strong optical absorption,which matches the solar energy spectrum.It can be used for solar driven interfacial water evaporation.Hollow CoSn(OH)₆ nanomaterials can be obtained by etching CoSn(OH)₆ with sodium hydroxide(Na OH).Hollow CoSn(OH)₆@ICG@AIPH(HCIA)nanoparticles was synthesized by combining hollow CoSn(OH)₆ nanoparticles with indocyanine green(ICG)and anoxic active prodrug 2,2'-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride(AIPH).It can be used as photothermal conversion materials for tumor treatment.(2)The Co-Sn alloy was deposited on the surface of the polytetrafluoroethylene(PTFE)film by vacuum filtration method,and the Co-Sn alloy-1@PTFE photothermal film was obtained.To further improve its light-to-heat conversion efficiency(?),a water evaporator based on a Co-Sn alloy@PTFE film and super-absorbent polymer(SAPs)was designed,which significantly improved the?value of the film from 53%to 89%.Besides,it also has excellent dye purification and heavy metal ion removal capabilities.The as-prepared evaporator has excellent surface mechanical properties.The theoretical calculation reveals the possible mechanism of high surface mechanical properties between Co-Sn alloy and PTFE membrane.(3)It is found that hollow CoSn(OH)₆ has oxidase activity and can release singlet oxygen free radical(~1O₂).ICG is an excellent photosensitizer and photothermal agent.It reacts with oxygen under the excitation of near-infrared light to produce ~1O₂ and heat.AIPH can overcome the hypoxic environment inside the tumor and produce toxic alkyl free radicals to kill tumor cells under the condition of no oxygen.Therefore,this chapter combines the three substances to synthesize HCIA nanoparticles,which show photothermal properties and biosafety.In the study of mouse breast cancer cells,HCIA nanoparticles produce heat and promote the release of ICG and AIPH,as well as the formation of singlet oxygen and alkyl radicals,under the laser irradiation of 808 nm.The combination of photothermal/photodynamic/enzyme catalysis can inhibit the growth and proliferation of tumors.