| In the 21st century,the shortage of resources has become a huge challenge for humanity.As a clean energy source,light energy has attracted attention due to its inexhaustible and renewable characteristics.How to effectively use light energy is an effective way to alleviate resource shortage.LaB6 as one of photothermal conversion material showed broad application in the development and utilization of light energy,heat insulation materials,hyperthermia and other fields due to its excellent near-infrared light absorption,high strength,high hardness,chemical stability and other characteristics.Lanthanum hexaboride(LaB6)nanocrystals were successfully synthesized at 700? for 2 h under argon atmosphere by a low-temperature molten salt method using LaCl3 and NaBH4 as reactants,NaCl-KCl or NaCl-KCl-Zinc as reaction melt.The obtained products were characterized by XRD,SEM,TEM and Raman spectroscopy.XRD patterns and Raman spectra confirmed the formation of LaB6 with high purity.LaB6 powders prepared in mixed molten salts of NaCl-KCl were mainly composed of nanoparticles with sizes of ca.8nm.The particle size of LaB6 prepared in NaCl-KCl-Zn system was larger,which indicated that the addition of zinc has a significant effect on the morphology of the sample.Photothermal conversion test showed that nanoparticles had a good photothermal conversion performance.To verify the versatility of synthesis of rare earth metal borides by low-temperature molten salt method,porous CeB6 nanostructure was successfully synthesized at 700? for 2 h under argon atmosphere by a melt-assisted method using CeCl3 and NaBH4 as reactants,NaCl-KCl as reaction melt.The obtained products were characterized by XRD,SEM,TEM,Raman spectroscopy and BET.XRD pattern and Raman spectrum confirmed the formation of CeB6 with high purity.CeB6 powder had mesopore structure and consisted of nanoparticles with mean size of 8 nm.Porous CeB6 had high surface area of 64.14 m2·g-1 and pore volume was 0.132cm3·g-1.LaB6 powder was synthesized by low-tempeature zinc melte method using LaCl3 and NaBH4 as reactants in the zinc melt.The effects of reaction temperature and zinc melt content on phase,composition,morphology and photothermal conversion performance of the products were studied.The prepared samples were characterized by XRD,SEM,TEM,HRTEM,BET and EDS.The obtained samples were all single phase LaB6 with different morphologies.The surfaces of LaB6 particles were coated with a partially oxidized amorphous boron.LaB6 nanoparticles can be prepared at 400? by zinc melt method,LaB6 prepared at 600? has a porous structure.When the amount of zinc increased,cubes began to appear in the samples prepared at 600?.As the reaction temperature increased to 700 ?,the amount of cubes increased significantly.LaB6 nanoparticles had better photothermal conversion performance and excellent photothermal stability.Mesoporous LaB6@calcium silicate composite with a core-shell structure has been prepared at 72 ? for 20 min via a sonochemical method using LaB6,Ca(NO3)2 and TEOS as raw materials.The obtained products were characterized by XRD,SEM,TEM,BET,HRTEM and EDS.The results showed that LaB6 nanoparticles were coated by calcium silicate nanosheets.The specific surface area of LaB6@calcium silicate composite was larger than that of LaB6 nanoparticles.Photothermal conversion test indicated that both LaB6 nanoparticles and LaB6@calcium silicate composite showed superior photothermal conversion performance,and the amount of calcium silicate had an effect on the photothermal conversion property of the composite.LaB6 nanoparticles and porous LaB6@calcium silicate composite were explored as drug carriers.IBU release percentages of LaB6@calcium silicate composites were all more than 65%,much higher than that of LaB6 nanoparticles,LaB6@calcium silicate composite showed a favorable release property for IBU in SBF. |
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