Controlled Synthesis Of Pd,Au-Pd Nanocrystals And Exploration Of Their Catalytic Properties

Metal nanocrystals have been actively investigated in recent years due to their unique properties and applications related to catalysis and others.A large number of studies have show that the properties of metal nanocrystals are strongly depend on both size and shape,especially when used as catalysts.Presently,how to improve the performance of the catalysts and save the economic costs,in other words,how to optimize the composition,size,structure and shape of the catalytic have drawn researches’ attention.In this thesis,we focus on the design and synthesis of novel gold and palladium nanocrystals,and the as-prepared nanocrystals disolayed robust catalytic performance in Suzuki coupling reaction.The main research results are summarized as follows:1.Briefly review on nano-related theories,synthetic approaches,current research status of bimetallic nanocrystals and summarized research development of Au,Pd.2.Synthesis of high index nanocrystalline and frame nanocrystalline.Palladium concave nanocubes enclosed by high-index {730} generate via manipulating the growth kinetics.Pd nanoframe were synthesized by controlling the rate of the oxidative etching and growth.3.We demonstrate the synthesis of a new type of hybrid nanostructures consisting of a Au octahedron core and a Pd frame shell.The formation of such morphology involved the heterogeneous,epitaxial growth of Pd on Au octahedral seeds,and the subsequent face-selective etching of Pd.It is expected that these Au@Pd-frame nanocrystals,combining the properties from both Au octahedrons and Pd frames,could further enhance the catalytic properties of Pd frames.4.When they as the catalysts for Suzuki coupling reaction,concave nanocubes and Pd frame nanocrystals exhibit high catalytic activities.The inner octahedral Au nanocrystals can act as the plasmonic component for efficient light absorption while the frame Pd segment act as the active catalyst.Compared with the previous Au@Pd nanocrystals,one of the main advantages is that the overgrowth of Pd frames on Au nanocrystals won’t markedly decrease the light absorption of the Au nanocrystals,thus can maximally enhance the catalytic activity of Pd frames.