Study On The Preparation And Electrooxidation Performance Of Pd-based Anode Catalyst For Direct Ethanol Fuel Cell

Direct ethanol fuel cells(DEFC)have been attracting more and more attention from researchers due to its high power density,high energy-conversion,sustainable regeneration and pollution-free.However,the insufficient catalytic activity and high catalyst cost hinder the commercialization of DEFC.Therefore,the preparation of catalyst with high catalytic activity and low price is the key factor to realize the commercialization of DEFC.In this dissertation,the direct ethanol elect electrooxidation catalyst are investigated from two aspects of catalyst structure and effective elements.In order to improve catalytic activity of cataysts,Ni element with low-cost and good catalytic performance was used as cocatalyst metal for Pd catalysts.Besides,hollow-nanoporous structure was introduced to increase electrocatalytic activity area of catalysts.The H-PdNi catalysts with different Pd/Ni ratios had been synthesized.The electrocatalytic activity of H-PdNi catalysts have been investigated.In order to improve the stability of H-PdNi catalysts,with the help of TiO2 support,the double-shell PdNi/TiO2 catalysts were successfully prepared by combing galvanic displacement method and in-situ reduction method.The H-PdNi and PdNi/TiO2 catalysts were characterized by scanning electron microscope(SEM),transmission electron microscope(TEM),energy dispersive analysis of X-ray(EDX),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),and the electrochemical performance of the catalysts were investigated by cyclic voltammetry(CV)and chronoamperometry(CP).The main conclusions are presented as follows:(1)The H-PdNi catalysts with hollow nanoporous structure were successfully synthesized by combining template method and electrochemical displacement method with the help of SiO2.H-PdNi catalysts with different Pd/Ni ratios were prepared by controlling the amount of Pd precursor and the electrochemical performance toward the ethanol electrooxidation(EOR)of H-PdNi catalysts were denonstrated by CV and CP in alkaline soultion.The results show that compared with commercial Pd/C(JM)catalyst,the catalytic activity of H-PdNi catalysts are higher than that of Pd/C(JM)catalyst.Amongst H-PdNi catalysts,the peak current density of H-PdNi3.i catalyst is about 4 times of that of Pd/C(JM)catalyst,holding great promise in application of direct ethanol fuel cells(DEFC).(2)Based on the preparation of hollow nanoporous H-PdNi catalysts,PdNi/TiO2 catalysts were prepared with TiO2 as template.With the help of Au nanoparticles,Ni nanoparticles were firstly prepared by a seed mediated growth method.Then,PdNi/TiO2 catalysts were prepared by combining the electrochemical replacement method and in-situ reduction method.Results show that the PdNi/TiO2 catalysts possess better electrocatalytic performance for EOR compared with Pd/C(JM)catalyst.Moreover,the anti-poisoning ability of PdNi/TiO2 catalysts are higher than that of H-PdNi catalysts.