Fabrication Of Palladium And Its Nanocomposites By Soft Template Method And The Study Of Their Catalytic Properties

Nanomaterials have attracted a lot of research interest because of their potentialapplications in chemistry, electronics, energy, environmental protection, medicine andcatalysis. Pd nanomaterials play an important role in the field of catalysis, researchershave prepared a variety of Pd and its nanocomposites and applied them to a variety ofcatalytic reaction. The size of the Pd nanoparticles, the morphology and composition ofthe materials are main factors which influence the catalytic performance of Pd and itsnanocomposites. Therefore, controllable fabrication of Pd and its nanocomposites byappropriate methods is the key to get high-performance catalytic materials.Based on the above considerations, we have synthesized high-performance Pd andits nanocomposites mainly through the following two ways. Firstly, we synthesized Pdnanomaterials with a specific morphology by soft template method. The improvedmorphology could enlarge the active area and prevent the aggregation effectively,which will help to improve the catalytic activity and stability. Secondly, we synthesizedPd composite nanomaterials with specific morphologies by soft template method. Thecombination of different functional components, the support of the substrate materialand specific morphologies could improve the catalytic performance effectively. In thisthesis, we have synthesized Pd hollow nanospheres, PEDOT/Pd composite hollownanospheres and conducting polymer/Pd composite nanorings by soft template method and studied their catalytic performance in detail. The conclusions of this thesis are asfollows:1. We used RB-PdCl42-formed by an electrostatic interaction as sacrificial template andNaBH4as reducing agent to synthesize Pd hollow nanospheres by a simple soft-template method at room temperature. The hollow nanospheres with a diameter rangingfrom20to150nm were composed of many small particles with a diameter rangingfrom2to6nm. The hollow nanostructure made the material have larger active areasand better catalytic stability. Therefore, the Pd hollow nanospheres we preparedexhibited enhanced catalytic performance as electrocatalysts for the oxidation ofmethanol and formic acid.2. We used RB-PdCl42-as sacrificial template and EDOT monomer as reducing agentto synthesize PEDOT/Pd composite hollow nanospheres through a one-pot redoxpolymerization at80°C. The composite hollow nanospheres with a diameter rangingfrom20to150nm had a uniform morphology and Pd nanoparticles with a diameterranging from2to6nm were well-dispersed in PEDOT substrate, which made thecomposites have a good catalytic performance. The as-prepared PEDOT/Pd compositehollow nanospheres showed a good peroxidase-like catalytic activity and had a lowdetection limit of1.06μM (S/N=3) toward H2O2, affording their potential applicationsin biosensors and environmental monitoring.3. We used lamellar (CTA)2PdBr4complex formed by an electrostatic interaction assacrificial template and monomer as reducing agent to synthesize conductingpolymer/Pd composite nanorings by the redox reaction between template and monomerat90°C. The obtained composites showed a homogeneous nanoring morphology withdiameter in the200-600nm range and Pd nanoparticles with a diameter ranging from4to20nm were well-dispersed in the substrate. The support of the ring-like conductingpolymer enlarged the effective surface area of the Pd nanoparticles and improved thecatalytic stability at the same time. Therefore, PPy/Pd composite nanorings have showna better catalytic performance when catalyzing the reduction of p-nitrophenol.