Study On The Catalytic Performance Of Ethanol Oxidation Reduction And Oxygen Reduction Reaction In Nano-porous Pd Based Fuel Cell Catalysts

Direct methanol fuel cell?DEFC?has attracted much attention and interest because of its advantages such as high power density,safe and convenient fuel storage,and environmental friendly.In the commercial production,DEFC still faces challenges,such as slow electrode kinetics,low energy density of organic small molecules,and so on.In order to reduce the cost of fuel cell and improve the utilization efficiency of the catalyst.Reachers are working on the Pd based catalyst.In this paper,nanporous PdM?NP-PdM?catalyst?M was Mn,Y,Ce,Ta,Nb?is prepared by melting quenching combined with alloying method.The X ray diffraction?XRD?,X ray photoelectron spectroscopy?XPS?,scanning electron microscopy?SEM?,energy dispersive spectroscopy?EDS?,transmission electron microscopy?TEM?were used to characterize the material.At the same time,we studied the NP-PdM catalyst response to ethanol oxidation reaction?EOR?and oxygen reduction reaction?ORR?in alkaline conditions.The main research contents and conclusions are as follows:Method of using arc melting and melt spinning were Pd₁₅Mn₅Al₈₀,Pd₁₅Y₅Al₈₀,Pd₁₅Ce₅Al₈₀,Pd₁₅Ta₅Al₈₀ and Pd₁₅Nb₅Al₈₀ alloy strip,by dealloy prepared NP-PdMn,NP-PdY,NP-PdCe,NP-PdTa,NP-PdNb catalyst.Then,the catalysts were tested by XRD,XPS,SEM and TEM.The results show that the catalyst material has a porous structure with a pore diameter of about 5 to about 10 nm.Because of the addition M metal,the EOR catalytic activity has been significantly improved.The results showed that the electrochemical active surface area of NP-PdMn?64.9 m2/g?,NP-PdY?34.8 m2/g?,NP-PdCe?32.7 m2/g?,NP-PdTa?489.8 m2/g?,NP-PdNb?153.3 m2/g?were commercial Pd/C?11.7 m2/g?5.5 times 3 times,2.9 times,41.8 times and 13.1 times.With the peak current density of ethanol were 760 mAmg-1,1420 mAmg-1,1045.1 mAmg-1,1901.8 mAmg-1,587.9 mAmg-1,about the commercial Pd/C?400 mAmg-1?1.9 times,3.6 times,2.6 times,4.8 times and 1.5 times.The peak potentials were shifted 230 mV,190 mV,120 mV,270 mV and 170 mV,respectively.The results of the EOR stability test showed that the stability of NP-PdMn,NP-PdY,NP-PdCe,NP-PdTa,NP-PdNb catalyst was better than that of commercial Pd/C catalyst.The half wave potential of NP-PdCe,NP-PdTa,NP-PdNb catalysts showed a small shift.In addition,the quality activity of NP-PdCe,NP-PdTa,NP-PdNb catalysts?at 0.875 V potential?is about 3.5 times,3.5 times and 3.1 times than the commercial Pd/C catalyst.The half wave potential was shifted to 10 mV,1 mV and 19 mV after 5000 cycles,respectively.The catalysts of NP-PdMn,NP-PdY,NP-PdCe,NP-PdTa and NP-PdNb samples are the anode and cathode catalysts for direct alcohol fuel cells which are better than commercial Pd/C.