Preparation And Catalytic Performance Of Palladium-Polyacid Composite Nanomaterials

In recent years,direct alcohol fuel cells have attracted much attention due to their advantages such as cleanness and high energy efficiency.Noble metal materials possess good application prospect in electrocatalysis for direct alcohol fuel cells.Among them,palladiumbased nanocomposites have received considerable interest owing to the good electrocatalytic activity and stability towards the alcohol oxidation reaction under alkaline conditions.However,the controllable synthesis of Pd-based electrocatalysts with low cost,high catalytic activity and good stability still needs to be deeply explored.Therefore,many efforts have been devoted into developing novel electrocatalysts with good electrochemical activity and stability.Besides,polyoxometalates have been developed in electrocatalysis in recent years.In this dissertation,Pd₃Pb/RGO/HPW,AuPd/CB/HPW and Pd/MPC/HPW composite nanomaterials were prepared by simple methods.The morphology,structure and chemical composition of the composites were analyzed by characterizations like transmission electron spectroscopy,X-ray diffraction,Raman spectroscopy,and X-ray photoelectron spectroscopy.In addition,the electrocatalytic behaviors of the prepared composites were measured by cyclic voltammetry and chronoamperometry in alkaline media.The experimental results show that the prepared Pd₃Pb/RGO/HPW2 and Pd/MPC/HPW-3 composites possess good mass activity and stability towards the electro-oxidation of methanol,ethanol,ethylene glycol and glycerol,while AuPd/CB/HPW-5 composite shows better electrocatalytic performance towards ethylene glycol and glycerol oxidation in comparison with commercial 10% Pd/C catalyst.The utilization of carbon materials as support can enlarge the electrochemical active surface area,and the introduction of phosphotungstic acid is capable of improving the electrocatalytic performance of the composites.