Preparation Of Nano-alloy/MWCNTs Catalyst And Its Bifunctional Electrocatalytic Performance

Direct ethanol fuel cell(DEFC)has attracted more and more attention of researchers due to its unique advantages such as safe use of ethanol,abundant sources,low price,easy portability and storage.However,the complete oxidation of ethanol to carbon dioxide involves 12 The transfer process of individual electrons,the breaking of C-C bonds and more adsorption intermediates lead to reduced catalytic efficiency.The development of high-efficiency and low-cost catalysts is one of the problems that must be solved in the commercialization of direct ethanol fuel cells.The main research contents of this paper are as follows:(1)The PdCo_x/MWCNTs nanoalloy catalysts with different molar ratios of Pd Co were prepared by a controllable synthesis method.The composition and morphology of the material were characterized by XRD,Raman and TEM tests.The results show that the particle size of Pd Cox/MWCNTs is relatively large,and the average particle size of Pd Co₃/MWCNTs is the smallest,about 31.70 nm.The dual-function electrochemical performance test of Pd Cox/MWCNTs in ethanol has been conducted.The electrochemical test results show that under alkaline conditions,the ECSA(50.53 m²g^-1)of Pd Co₅/MWCNTs is the largest,which is Pd/MWCNTs(4 m²g^-1)The peak potential of the CO oxidation peak of Pd Co₃/MWCNTs is negatively shifted by 0.43 V from the peak potential of the CO oxidation peak of Pd/MWCNTs,which proves that it has the strongest ability to resist CO poisoning.In ORR,the maximum limit current value of PdCo₃/MWCNTs is-2.52 m A cm^-1,which is 0.93 m A cm^-1 higher than the limit current value of Pd/MWCNTs(-1.59 m A cm^-1),which proves the electron transfer of Pd Co₃/MWCNTs in ORR The fastest and the highest reaction efficiency,n is 3.50?3.70,which proves that the reaction is 4 electron transfer.(2)PdMo_x/MWCNTs nano-alloy catalysts with different mass ratios of PdMo were prepared by a controllable synthesis method.The composition and morphology of the material were characterized by XRD and SEM tests.The results showed that PdMo was successfully loaded onto MWCNTs;the particle size of PdMox/MWCNTs was relatively large.Electrochemical test results show that under alkaline conditions,the ECSA(4.37m²g^-1)of PdMo/MWCNTs is the largest,which is 2.3 times that of Pd/MWCNTs(1.88m²g^-1);the reaction efficiency of PdMo/MWCNTs in ORR reaction is relatively high,n is 2.55-2.57.(3)PtMo_x/MWCNTs alloy catalysts with different mass ratios of Pt Mo were prepared by a controlled synthesis method.The composition and morphology of the material were characterized by XRD,Raman,SEM,TEM and EDS tests.The particle size of Pt Mox/MWCNTs is relatively uniform,and the average particle size of Pt Mo_1.5/MWCNTs is the smallest,about 5.31 nm.The electrochemical test results showed that among the prepared catalysts,the ECSA value of Pt Mo_1.5/MWCNTs was the highest at 43.35 m²g^-1.The CV test of Pt Mo_1.5/MWCNTs in ethanol showed that the mass catalytic activity value of I_f was 610.35 m²mg_Pt^-1 is 1.4 times that of ETEK(436.89 m²mg_Pt^-1),which proves that Pt Mo_1.5/MWCNTs has a stronger ability to oxidize ethanol,and the stable mass activity is 140.62 m A mg_Pt^-1,which is 1.2 times of ETEK(115.27 m A mg_Pt^-1)It is proved that its stability is better than ETEK.