Study On Metal Nano-catalyst Prepared By Biological Reduction

Palladium plays excellent catalytic activity in petrochemical and organic synthesis.Many methods have been used for preparing palladium nanoparticles,such as chemical,physical,electrochemical and biological method.Recent years,eco-friendly method has been concerned much.Biological way,as widely materials,mild reaction conditions,no additional chemical reagents,and less toxic byproducts,has been researched much.Meanwhile,considering the extremely important role played by the noble metal catalysts in chemical industry by right of their unique catalytic activity and selectivity,consequently it is believed of great interest to develop supported noble metal catalysts through bio-reduction.Based on the above,this paper aims to prepare palladium by different plant leaf water crude extract and supported catalysts,and study their application in hydrogenation:Palladium nanoparticles are prepared by use of Ginkgo and Cinnamomum camphora leaf extract in the chapter 3 of this article.The three aggregation states of the solution after the reaction by Ginkgo biloba extract are characterized and investigated the mechanism of formation of nanoparticles and only generated"palladium membrane"on the surface of the solution is Characterized and analyzed after the reaction by Cinnamomum camphora leaf extract.The use of single factor experiments investigated the stirring speed,reaction temperature,reaction time response to the evaluation.Three factors and three levels of experimental design on the basis of single factor experiments,the use of response surface methodology（RSM）in the Box-Benhnken module styrene conversion rate as the response value,response surface analysis,optimization and experimental verification,draw the most the best process parameters for the reaction in the chapter 4.By using biological reduction method as palladium active component load method,preparation of the high degree of dispersion load type series catalyst.Using XRD,TEM and EDS and specific surface representation method,investigation and analysis of the biological and chemical reduction method for preparation of palladium catalyst of the physical and chemical properties and catalytic action the essence of the difference of these.The following conclusions are got through the above analysis:1、Ginkgo and Cinnamomum camphora leaf extract have a good reduction and different morphology palladium nanoparticles can be prepared by the different plant extract.The agglomeration state palladium nanoparticles are triangular,spherical,quadrilateral,hexagonal and other irregular shapes by the use of Ginkgo extract liquid and wider particle distribution,the larger particle size,particle size distribution ranging from 10-40nm.However,palladium nanoparticles average particle size is about 4nm and particle size distribution and narrow dispersion and mainly are spherical particles by Cinnamomum camphora leaf extract.The study found that reducing biomass hydroxyl,carbonyl,amino group played a reduction in the restore process.2、Through the use of response surface methodology for the study of the of styrene hydrogenation process conditions styrene conversion rate of the reaction temperature,reaction time,the regression model of the hydrogen flow,demonstrated by analysis of variance model is reasonably reliable and better able to predict experimental as a result and draw the most the best process parameters for the reaction temperature was 67.24°C,reaction time 2.95h,the hydrogen flow rate 150ml/min,the yield of 100.00%.3、we can get the following conclusions by the characterization and activity evaluation on the supported palladium nano-catalyst:Pd²⁺can be directly reduced to Pd⁰and load on the carrier as the active component by bio-reduction with the use of Ginkgo life extract.The results showed that compared with the chemical load method,the legal system for biological catalyst has showed higher activity and stability.