Preparation And Catalytic Performance Of Supported Palladium Nanoparticle Composite Catalyst

Noble-metal nanoparticles,especially palladium(Pd)nanoparticles,have been widely studied as catalysts because of their high catalytic activity in many organic catalytic reactions.Noble-metal nanoparticles of catalytic activity depends on their size,morphology,crystallinity and surface state,but its itself has some shortcomings,such as easy to reunite,poor stability and difficult to recycle,greatly reduces the catalytic performance.Pd nanoparticles will load on the appropriate carrier,synthesis of functional composite catalyst supported Pd nanoparticles,improve the morphology and size distribution of Pd nanoparticles,optimization and carrier,the synergy between material and improve the overall catalytic activity.The main research contents of this paper include the following two parts:First,we designed a series of yolk/shell FexOy/PdPt@CeO2 composites,in which FexOy nanoparticles acted as a movable core,allowing for the uniform distribution of the PdPt alloys on the inner surface of the CeO2 shell.Due to the high porosity and porosity of CeO2 shells,FexOy/PdPt@CeO2 composite materials can be used as nano-reactors for catalytic reactions.At the same time,we also found two structural characteristics that led to the enhanced catalytic activity of catalysts,including the substitution of bimetal PdPt alloy for single metal nanoparticles.Reactive CeO2 shells were used instead of chemical inert carriers.The catalytic reduction activity of nanocatalysts was higher than that of control samples.In addition,because of its magnetic properties,the catalyst is easy to be recovered and reused.Second,a reduced graphene oxide nanosheet/glutathione-Pd(r GS/G-Pd)hydrogel was synthesized by hydrothermal method.In the process of synthesis,glutathione not only with the graphene oxide nanosheet(GS)on the surface functional groups of the reactions and improved the crosslinking degree of the hydrogel,and improves the conductivity depth reduction GS.In addition,the size of Pd nanoparticles was effectively reduced to only 1.7 nm by the coordination between functional groups in glutathione molecule and Pd2+.The resulting hydrogel forms a three-dimensional layered porous structure,and the ultra-small Pd nanoparticles are evenly distributed on the surface of the hydrogel.In heterogeneous catalytic reactions,the catalytic reduction activity of r GS/G-Pd hydrogels was higher than that of the control samples without glutathione,which could be used as an appropriate catalyst.