Preparation And Characterization Of Pd-based Anode Catalyst For Alkaline Direct Ethanol Fuel Cells

Direct ethanol fuel cell(DEFC),a green and environmental device,has received widespread attention,due to its high energy-conversion efficiency,specific power and energy density.However,the insufficient performance and high cost of the catalysts restrict the development of DEFC.Thus,the development of the catalyst with excellent performance and low cost is one of the key factors to commercialize the DEFC.The work was carried out from the aspects of catalyst element and structre.The binary or triple Pd-based catalyst with hollow porous or supported structure was prepared using the oxyphilous metal Sn and Ni to improve the catalytic performance.The physical and chemical properties of the as-prepared catalysts were characterized.The electrochemical performance of catalysts were evaluated.The main work are as follows:(1)The hollow porous PdSnNi nano-catalysts were successfully synthesized by using sacrificial template method and current displacement method.H-PdSnNi catalysts were obtained by current displacement reaction between metal precursor solution and hollow Ni microspheres,which were prepared by using silica microspheres as hard templates.HR-TEM images illustrated that H-PdSnNi catalysts with nanochannels were successfully obtained,and Pd,Sn and Ni elements were distributed well.The electrochemical performance test showed that the enhancement of electrochemical performance towards the ethanol electrooxidation of the H-PdSnNi catalysts in comparison with Pd/C(JM).The oxidation activity is much higher than that of Pd/C(JM),and the residual current density after stability test is 7.1 times of Pd/C(JM).(2)PdSn/CNT catalysts were successfully synthesized by microwave assisted polyols and in-situ reduction.Sn nanoparticles were prepared by microwave assisted polyols.Then,the precursor solution of palladium was reduced on Sn nanoparticles surface to form composite nanoparticles followed by loading on the carbon tubes.TEM images exhibited that composite nanoparticles were dispersed well on the carbon tubes without aggregation.CV and CA demonstrated that the prepared catalysts had excellent oxidation performance of ethanol.In addition,the current density can be recovered by a simple cyclic potential scanning in an alkaline condition after the CA test.