Fabrication Of Pt,Pd-based Catalysts In Deep Eutectic Solvent For Catalytic Oxidation Of Small Organic Molecules

This thesis put emphasis upon preparation of Pt,Pd-based catalysts in DESs by chemical reduction method as the anode catalysts for direct methanol or formic acid fuel cells.The main original results are as follows:(1)The Pt/MWCNTs-D catalyst was prepared by mixing method in DESs.The reaction conditions were optimized:80?,p H=9,3 hours,and molar ratio of Na BH₄/H₂Pt Cl₆=10/1.Electrochemical tests showed that Pt/MWCNTs-D held higher electrocatalytic activity,stability,and excellent resistance to CO toxicity than Pt/MWCNTs-25 and commercial Pt/C.(2)The Pt₉Sn₅three-dimensional alloy nanonetwork catalyst(Pt₉Sn₅/MWCNTs-D)was prepared by mixing method in DESs.The catalyst(Pt₉Sn₅/MWCNTs-600)was obtained by further pyrolysis in N₂atmosphere at 600?for 2 h.Electrochemical tests showed that Pt₉Sn₅/MWCNTs-600 held higher electrocatalytic activity,stability,and excellent resistance to CO toxicity than Pt₉Sn₅/MWCNTs-D,Pt/MWCNTs-D and commercial Pt/C.Density functional theory(DFT)calculation showed that proper pyrolysis can improve the resistance to CO toxicity for catalyst.(3)The Pd₁Ce_0.5alloy nanonetwork catalyst(Pd₁Ce_0.5/MWCNTs-D)was prepared by mixing method in DESs.Electrochemical tests showed that Pd₁Ce_0.5/MWCNTs-D held higher electrocatalytic activity,stability,and excellent resistance to CO toxicity than Pd/MWCNTs-D,Pd/MWCNTs-W,and commercial Pd/C.(4)The ultrafine Pd₃Ag_0.5alloy catalyst(Pd₃Ag_0.5/MWCNTs-D)was prepared by solvothermal method in DESs.Electrochemical tests showed that the Pd₃Ag_0.5/MWCNTs-D catalyst exhibited higher electrocatalytic activity,stability,and excellent resistance to CO toxicity than Pd₃Ag_0.5/MWCNTs-W,Pd/MWCNTs-D,and commercial Pd/C.DFT calculation showed that the doping of Ag will change the electronic structure and d-center of Pd for improving the resistance to CO toxicity for catalyst.(5)A series of ternary alloy catalysts(Pd₃Co₁Ni_x/MWCNTs-D)(X=2,1.5,1,0.75,0.5,0.25,0.1)with different Ni content(fixed the amount of Pd and Co)by solvothermal method in DESs.Electrochemical tests showed that the Pd₃Co₁Ni₁/MWCNTs-D catalyst exhibited the highest electrocatalytic activity,stability,and excellent resistance to CO toxicity than Pd₃Co₁/MWCNTs-D,Pd₃Ni₁/MWCNTs-D,Pd/MWCNTs-D and Pd₃Co₁Ni₁/MWCNTs-W.DFT calculation showed that the better resistance of Pd₃Co₁Ni₁/MWCNTs-D to CO poisoning was attributed to the double doping effect of Co and Ni.