Preparation And Electrocatalytic Properties Of Pt Alloy Nanostructures With Special Morphology

In this thesis,Pt-Pd-Cu nanoparticles with truncated-octahedral nanostructure,Pt-Co nanoparticles with polyhedral-nanostructure and Pt-Cu nanoparticles with porous structure were prepared by solvothermal method.First,the effects of reaction temperature,reaction time,reaction precursors and surfactants on the morphology and microstructure of Pt-based alloys were investigated.Then,the morphology,structure and composition of the samples were tested by Transmission electron microscope,High resolution-transmission electron microscope,X-ray diffractometer,X-ray photoelectron spectroscopy and Inductively coupled plasma-optical emission spectrometer.In addition,the electrochemical properties of Pt-based alloys were studied by cyclic voltammetry and chronoamperometry.The results showed that the prepared Pt-based catalyst exhibited better catalytic activity and stability toward the oxidation of formic acid than commercial Pt black.The Pt-Pd-Cu nanoparticles with truncated-octahedral nanostructure were prepared in ethylene glycol solution by solvothermal method using acetylacetone salts as metal precursors and potassium bromide and polyvinylpyrrolidone as surfactants,and the morphology and properties were characterized.By changing the experimental conditions,the effects of various conditions on the morphology of the products were studied.Moreover,the formation mechanism of Pt-Pd-Cu truncated octahedral structure was studied by means of transmission electron microscope,inductively coupled plasma-optical emission spectrometer and other characterization methods.In addition,the Pt-Pd-Cu catalyst was electrochemically tested.The results showed that the Pt-Pd-Cu catalyst had better catalytic activity and stability than commercial Pt black.In ethylene glycol solution,the Pt-Co nanoparticles with polyhedral-nanostructure were prepared by solvothermal method using platinum acetylacetonate and cobalt acetylacetonate as metal precursors,potassium bromide and polyvinylpyrrolidone as surfactants,and the morphology and properties were characterized.Based on the experiment results,it could be seen that Pt-Co alloys had the best microstructure when the reaction temperature was 150?,the reaction time was 24 h,and the molar ratio of reaction precursor was 1:1.The nanocrystal size was 9?10 nm.Moreover,the electrochemical tests were carried out.According to the results,it could be seen that Pt-Co nanoparticles hadbetter catalytic activity and stability than commercial Pt black.The Pt-Cu nanoparticles with porous structure were prepared by solvothermal method using N,N-dimethylformamide as reductant and solvent,platinum acetylacetonate and copper acetylacetonate as precursors,and the morphology was characterized.The results showed that the Pt-Cu alloy exhibited porous structure when the reaction temperature was 150?,the reaction time was 24 h,the 1uality of polyvinylpyrrolidone was 0.05 g and the 1uality of potassium bromide was 0.05 g.