Controllable Synthesis Of Platinum Based Alloyed Nanocrystals For Their Catalytic Properties Study

The depletion of traditional fossil fuels and environmental pollution increasing has forced people to explore new clean energy.Fuel cell with its high energy efficiency,clean emissions are increasingly concerned and favored by various industries.However,as the key technology and the main cost of the fuel cell,Pt based catalysts' performance is still not suitable for large-scale commercial using.Therefore,it is urgent for us to develop high catalytic performance platinum based catalysts.In this paper,the design,controllable synthesis and properties of porous/hollow platinum based catalysts were studied.In order to prepare high activity and high stability platinum based catalysts,to reduce the amount of fuel cell platinum,reduce the cost of fuel cells,and ultimately achieve the purpose of commercialization using fuel cell.Specific work as follows:1.Porous Pt Ag alloy nanoparticles were synthesized by seed growth method.By adjusting the dosage ratio of Ag NO3 and H2 Pt Cl6 in the growth solution,the morphologies of the porous alloyed nanocrystals can be tuned from multipetals to multioctahedra and the alloy composition can be varied from Pt76Ag24 to Pt66Ag34.We realized the simultaneous adjustment of the morphology and composition of Pt based catalyst.The catalytic reduction of p-nitrophenol and electrocatalytic oxidation of methanol showed that the Pt Ag alloy nanoparticles,especially the porous octahedra Pt70Ag30 nanoparticles,showed high catalytic activity and stability.It suggested us that the catalytic properties of Pt based nanoparticles can be improved by controlling the morphology and composition of Pt nanoparticles.2.We utilize the different reduction rate between Pd Cl22-and Pt Cl62-to obtain Pd core and Pd-Pt alloy shell,and then etching the Pd core by oxygen in air to synthesis Pt Pd nanodendritic,nanosakura and nanocage.By increasing the dosage of Pd precursor,hollow Pt Pd bimetallic nanoparticles' pore size,shell thickness and elemental composition can be controlled.The Pt Pd bimetallic nanoparticles have excellent methanol oxidation catalytic activity,the carbon supported porous hollow nanosakura Pt32Pd68 has excellent electrocatalytic stability,after 1000 cycles the activity of MOR can still maintain 96.69%.