Synthesis Of Bimetallic Nanoparticle For Catalytic Hydrogenation Applications

It is well known that most of hydrogenation catalysts are noble metals,which are rare earth resources and highly expensive.Thus,the developing trends in catalytic hydrogenation lie in reducing noble metals dosage,maintaining even promoting catalytic activities at the same time.In this dissertation,two kinds of bimetallic nanoparticles were synthesized.Then the bimetallic nanoparticles were used in the catalytic hydrogenation of unsaturated organic compounds and unsaturated elastomers.This thesis concludes the following two parts:(1)The palladium nanoparticles(Pd NPs),copper nanoparticles(Cu NPs)and PdCu bimetallic nanoparticles(BMNPs)were prepared which employed polyvinylpyrrolidone(PVP)as stabilizer agent and L-ascorbic acid(AA)as reductant.We employed X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),Energy dispersive spectrometer(EDS),Transmission electron microscope(TEM)and High resolution transmission electron microscopy(HRTEM)to characterize the synthetic nanocatalysts.The results suggest that the structures of PdCu BMNPs are alloy structures and the size of synthesized PdCu BMNPs are about 3.4 nm,which are smaller than Pd and Cu NPs.We prepared PdCu BMNPs of different morphologies by adding potassium iodide(KI)and potassium chloride(KCl)to investigate the morphologies of PdCu BMNPs on the influence of catalytic activity.The results show that the spherical PdCu BMNPs with smaller size have best catalytic performance.In addition,the influence of synergistic effects on the catalytic activity was explored,which turned out that under the same hydrogenation conditions,the catalytic activities were decreased in the following sequence,Pd NPs>PdCu BMNPs>Cu NPs.(2)We employed PVP as stabilizer agent and various reductants to prepare a series of palladium-ruthenium(PdRu)BMNPs to explore the influences of reductants,microwave temperature and metal ratios on catalytic performances.It turns out that with the increase of the ratios between Ru and Pd,the catalytic activities of PdRu BMNPs are promoted in the beginning,then reduced.The hydrogenated degree(HD)reaches highest when the ratio between Ru and Pd is 7:3.Lastly,the optimal hydrogenation process parameters on the catalytic hydrogenation of hydroxyl-terminated butadiene-acrylonitrile copolymer(HTBN)were explored.The degree of hydrogenation reaches 90.5%under the optimum conditions.