Contolled Synthesis Of Platinum-Based Nanomaterial And Their Catalytic Performances

Precious metal nanomaterials not only have the physical phase properties such as chemical stability,conductance and high catalytic activity,but also possess unique optical,electrical and magnetic properties produced by nano-effects.Many precious metal nanomaterials with controllable shape,size and composition have been widely used in chemical catalysis,photoelectrocatalysis,biomedicine and environmental energy.Among them,Pt-based nanomaterials as a branch of precious metal nanomaterials,have an irreplaceable position in various catalytic fields.At present,owing to the high synthesis cost brought by the scarcity of Pt resources,the goal that scientists have been pursuing is to find an effective way to reduce the amount of Pt metal,while maintaining the excellent properties of the material.Therefore today,the focus of research at home and abroad includes the following two aspects: the introduction of Fe,Co,Ni and other cheap transition metals to form binary,ternary or even quaternary alloy nanomaterials,reduces the cost of synthesis;on the other hand,the adjustable factors,such as morphology,composition,electron transfer,lattice strain and surface element distribution in the material,which can been adjusted to improve the utilization rate of single Pt atom and stability of the nanomaterial,so as to maximize the economic benefits.This thesis mainly study the controlled synthesis of Pt-based nanomaterials in oleylamine-borane compound system and 1-octadecene system,respectively.The catalytic performance of these Pt-based nanomaterials was experimently evaluated using oxygen reduction electrocatalytic test(ORR),nitrobenzene and cinnamic aldehyde selective hydrogenation test as the model reaction.The main work content is summarized in the following two aspects:1.A series of Pt-on-Pd heterogeneous dendrites,Pd@Pt core-shell particles,PtPd alloy nanoparticles,PtPd@Pt core-shell particles and PtPd alloy nanodendrites with the different Pt/Pd ratios were obtained in oleylamine-borane system by adjusting the preparation parameters.And then,the characterization methods(HRTEM,EDS,XRD,XPS,etc.)were used to clarify the characteristics and differences between the nanomaterials with the various morphological structures.Finally,the relationship between structures and performance was analyzed in depth based on the PtPd nanomaterial structures and ORR test results.2.A series of Pt-based nanodendrites,Pd-based and Rh-based nanomaterials with different sizes and compositions were synthesized in the pure 1-octadecene system.The effects of different the precursor salts,the different reaction temperatures and time on the synthesis of Pt-based nanodendrites were studied.And then,the catalytic performances of the above synthsized Pt-based,Pd-based and Rh-based nanomaterials were evaluated by selective hydrogenation of nitrobenzene and cinnamaldehyde and analysed the differences in catalytic activity.After catalytic reaction,the morphology of the used catalysts were characterized by TEM in order to study the stability of the catalysts.