Preparation Of Pt-based Multiple Noble Metallic Nanomaterials And Their Electrocatalytic Oxidation Towards Methanol

Direct methanol fuel cell(DMFC)is always the research center of chemical power sources because of its merits:the availability of methanol,high theoretical energy density,good safety,and environment-friendlyness.However,conventional catalyst of DMFC is metallic Pt,which severely limits the wide applications of DMFC owing to the high price,low reserves,and weak durability of Pt catalyst.To address these issues mentioned above,scientists are devoted to designingPt-based composite catalysts so as to use the synergistic effect of different metals to reduce the cost and to improve the tolerance to CO-like poisoning intermediates,and have made great progress.Among all morphology-varied Pt-based multiple metallic catalysts,hollow structures seem to have much better catalytic activity than other solid structures due to its higher specific surface area and abundant active sites.Thus,developing hollow multi-component Pt-based catalysts may be helpful for solving the problems related to pure Pt catalyst.Herein,this thesis proposes one interface-confined strategy,successfully fabricating a series of Pt-based multiple metallic nanocups,and these nanocups inherit the structural feature of hollow structure,exhibiting excellent catalytic performance to methanol electrooxidation.(1)By employing Ag nanocubes as sacrificing templates,AgPt alloy nanocups were successfully fabricated by an water-air interface-confined strategy involving the ethanol-induced self-assembly of Au nanocubes and interfacial galvanic replacement between interfacial Ag nanocubes and Pt Cl₆^2-ions in the water phase.Various characterizations such as SEM and TEM were used to examine the morphology and composition of AgPt nanocups.Owing to the electronic and structural effects,AgPt nanocups show enhanced catalytic activity and durability:the specific activity of AgPt nanocups is?4 m A cm^-2,?2 times that of commercial Pt/C(2 m A cm^-2);after cyclic oxidation for 4000 s,the steady specific activity of AgPt nanocup is 0.74 m A cm^-2,?4.3 times that of Pt/C.(2)To further improve the catalytic performance of AgPt nanocup s,Au@Ag core@shell nano-cuboids were used as sacrificing templates,and by using the similar interface-confined strategy,Au-nanorod-in-AgPt(Au/AgPt)nanocups were fabricated involving the water-air interfacial self-assembly of Au@Ag core@shell nano-cuboids and interfacial galvanic replacement between interfacial Au@Ag core@shell nano-cuboids and Pt Cl₆^2-ions in the water phase.Due to the synergistic effect of three components,Au/AgPt nanocups exhibit better catalytic performance than AgPt nanocups:the specific activity of Au/AgPt nanocups is?6.6 m A cm^-2,?3 times that of commercial Pt/C and?1.7 times that of AgPt nanocups;after cyclic oxidation for 4000seconds,the steady specific activity of AgPt nanocup is still?6 times that of Pt/C,exhibiting robust catalytic durability.(3)To further enhance the catalytic performance,Au@Pd@Ag core@shell nanostructures were used as sacrificing templates,and by using the similar interface-confined strategy,dumbbell-shaped-Au@Pd-particle-in-AgPt(Au@Pd/AgPt)nanocups were fabricated involving the synthesis of Au@Pd@Ag core@shell nanostructures,the water-air interfacial self-assembly of Au@Pd@Ag core@shell nanostructures and interfacial galvanic replacement between interfacial Au@Pd@Ag core@shell nanostructures and Pt Cl₆^2-ions in the water phase.Due to the synergistic effect of four components,Au@Pd/AgPt nanocups exhibit better catalytic performance than Au/AgPt nanocups:the specific activity of Au@Pd/AgPt nanocups is?8.8 m A cm^-2,?9 times that of commercial Pt/C,?4.7 times that of AgPt nanocups,and?3 times that of Au/AgPt nanocups;after cyclic oxidation for 4000 seconds,the steady specific activity of Au@Pd/AgPt nanocups is?1.8 m A cm^-2,?10.6 times that of Pt/C,exhibiting the optimal catalytic durability among all Pt-based catalysts involved in this thesis..