Study On Preparation And Properties Of Noble Metal Nanocomposites

With the continuous development of nanotechnology in the field of life science,more and more new materials have emerged,such as nanomaterials.Because of the larger specific surface area and the properties of nanomaterials,nanoparticles have been paid much attention by researchers.Noble metal nanoparticles also have surface plasmon resonance(SPR)effect,giving them some special properties,such as the growth of gold nanoparticles and the ability of silver nanoparticles to enhance their photocatalytic activity.Nanogold has good photothermal conversion ability and can be used for photothermal treatment.Poloxamer 407(F127)has good biocompatibility,biodegradability,temperature sensitive and non-toxic.And poloxamer 407 also has good effects of surfactant and solubilization.The photothermal heating of nanogold is fast,and it can hurt normal tissue cells.Therefore,if phase change energy storage material can be combined,when the temperature is too high,it will absorb its heat and control the temperature in a certain range,thereby reducing the damage of normal cells.The n-octadecane(C18H38)and paraffin wax(Petrolin)are commonly used as phase change energy storage materials.In this paper,through the physical reaction,the AuNPs/F 127/PCM composite hydrogel was prepared,and it has temperature sensitivity and photosensitivity that can gel in the light.Nanosilver has some special properties,such as good electron transport capacity,surface effect and quantum size effect.It can be combined with other photocatalytic materials and improve photocatalytic efficiency.Therefore,in order to improve the photocatalytic performance of g-C3N4 composites,the effect of C/Ag nanocomposites on the properties of g-C3N4 was also studied.The main contents are as follows:(1)Nanogold was prepared by sodium citrate reduction method first,and was characterized by SEM,XRD,heating test and other methods.The prepared gold nanoparticles are spherical.They can be heated under illumination,and the capacity of photothermal is good.The AuNPs/F 127 composite hydrogel was prepared by physical method and characterized by SEM and macroscopical observation.The AuNPs/F 127 composite hydrogel has voids structure,and nano gold has good dispersion in the network structure.By the measuring method,the photothermal capacity of AuNPs/F127 hydrogels were characterized.The results show that the nano gold in AuNPs/F127 hydrogels has good thermal capacity,and can promote the gelation of AuNPs/F127 hydrogels.(2)AuNPs/F127/C18H38 composite was prepared by physical composite method and characterized by SEM,FTIR and other methods.The results show that the AuNPs/F 127/C18H38 composite has a multi pore structure,and the C18H38 ia recombined in the AuNPs/F127by physical method.Through photothermal heating and natural cooling test,it shows that AuNPs/F127/C18H38 has certain temperature control ability when heating up,and the temperature control ability is better with the increasing of C18H38 content.AuNPs/F 127/paraffin composites were prepared by physical composite method.The AuNPs/F127 paraffin composites were test by the photothermal heating and natural cooling-The effects of different gold nanoparticles in the composites were tested.Compared with AuNPs/F 12 7/eighteen alkane,it is found that the temperature control range of the AuNPs/F 127/PCM composite hydrogel can be controlled by changing the phase change material.(3)The g-C3N4/C/Ag nanocomposites were prepared by hydrothermal reduction method.Scanning electron micrograph(SEM),X-ray diffractometer(XRD)and high resolution Fourier transform infrared(FTIR)were used to characterize the microstructure and chemical composition of the products.The UV absorption spectra of the products show that the addition of silver nanoparticles can improve the light absorption range and the visible light absorption intensity of the composite.In further studies,methylene blue was degraded with three samples with different reaction times in the reactor,and It was found that when the reaction condition was 180? and the reaction time was 6h,the photocatalytic degradation performance of the g-C3N4/C/Ag nanocomposites was the best.The g-C3N4/C/Ag nanocomposites were successfully prepared,and the photocatalytic performance is better than that of g-C3N4.