Synthesis,Characterization And Catalytic Performance Of Polyoxometalates-based Graphene Nanocomposites

Polyoxometalates known as metal oxygen anion clusters,they are widely used in the fieldof catalysis,medicine,surface science and materials science,but polyoxometalates have smallsurface area,and hard to separate,their potential application in other fields is limited.Graphenehas large surface area,excellent thermal performance and outstanding mechanical propertiesand so on.In this paper we chose polyoxometallates and graphene as building blocks,andprepared a series of polyoxometalates-based graphene nanocomposites in situ,we hope thecomposites have large surface area and ease to separate.this can greatly impove their catalyticperformance.Infrared Spectroscopy (FT-IR),Transmission Electron Microscopy(TEM),Thermogravimetric Analysis (TGA),X-ray Powder Diffraction (XRD),Raman Spectra(Raman) and specific surface area (BET)were used to characterise nanocomposites.On theother hand,We tried to synthesize berberine/graphene oxide composites,which has liquidcrystalline.The main results are as follows:1.Research and development Keggin type polyoxometallate-based graphene.We choseKeggin type polyoxometallate in situ preparing Keggin type polyoxometallates/GSnanocomposites, nanocomposites were characterized,the results showed that new chemicalbond was formed between polyoxometallates and graphene,The specific surface area is muchlarger than polyoxometalates,the specific surface area of SiW12/GS is as high as875m2/g.Thethermal stability of composites are better than graphene and polyoxometalates.In order tomeasure catalytic performance of nanocomposites,they are used as catalysts to catalyticoxidation of cyclohexene, the results prove the better catalytic performance of preparedcomposites.2. Research and development Dawson type polyoxometallate-based graphene.We chose P2Mo18as building block preparing P2Mo18/GS nanocomposites in situ, the results indicated that therewere strong ionic bond and hydrogen bond between graphene and P2Mo18,P2Mo18/GS hasspecific surface area as high as1065m2/g,which is much larger than PMo12/GS composites,thermal stability of P2Mo18/GS is better than graphene,its catalytic performance is good.3. Research and development graphene oxide/berberine composites.According to differentstoichiometry,we prepared a series of different loading composites.The results demonstratedberberine solution does not affect liquid crystalline of solution,when loading amount ofberberine is16%,the berberine/graphene oxide composite began to precipitate,so in order to keep the liquid crystalline,the loading amount should be less than16%,UV-vis spectraimplied that berberine and graphene oxide exist chemical bond.This results provide a newidea for further study of the drug release.