Study On Pd-based Anode Catalysts For Direct Glycerol Fuel Cell

In recent years,glycerol has been used as fuel for Direct alcohol fuel cells（DAFCs）due to its advantages of low price,environmental friendliness,easy storage and transportation.However,the commercialization process of Direct glycerol fuel cell（DGFC）still have many problems such as low catalyst activity,poor stability,high cost and so on.Therefore,designing an electrocatalyst with high activity,strong anti-poisoning ability,good stability,and moderate price is crucial to its development.In this paper,three supports and five elements are used to prepare supported Pd-based electrocatalysts.The crystal composition and spatial distribution,surface state and atomic distribution of Pd-based electrocatalysts are characterized by physical characterization methods such as XRD,TEM,XPS and ACTEM.Electrochemical research methods such as CV,CA and EIS investigated the effects of doping element types,ratio,calcination temperature,and types of functional groups on the carrier surface on the performance of Pd-based electrocatalysts.At the same time,the effect of changing the experimental conditions on the dispersibility and particle size of the Pd/C catalyst was investigated.The results show that when graphene oxide is used as the carrier,the Pd₆Pr₄/rGO catalyst exhibits the highest catalytic activity(5.08 A·mg_Pd^-1)for the electrooxidation of glycerol,the main reason is that the doping of the rare earth element Pr causes the metal particle size decrease.Using multi-walled carbon nanotubes with different functional groups as the carrier,when Pd:Pr=6:4,the Pd Pr/N-MWCNT nanocatalyst synthesized at 550℃has the best performance for the electrooxidation of glycerol,with a catalytic activity of 1.17 A·mg_Pd^-1is 2.75 times that of pure Pd.The reason is that the N atoms on the multi-walled carbon nanotubes provide Pd metal nanoparticles（Pd NPs）on the surface of the catalyst carrier with more electrons than-COOH,-NH₂and-OH,and there is a strong electronic effect between Pd and Pr and Synergistic effect,which makes the rate of electrooxidation of glycerol on Pd₆Pr₄/N-MWCNT catalyst with electron-enriched Pd-Pr NPs faster.The Pd/C catalyst synthesized under calcination at 500℃for 1 h under the hydrothermal condition of adding 750μl of H₂O₂and hydrothermal conditions at 200℃for 6 h has the best dispersion and the smallest Pd particle size.Under the transmission electron microscope with spherical aberration correction,Pd nanoparticles,Pd clusters and a small amount of Pd single-atom were observed on the catalyst surface.The Pd/C catalyst synthesized under this condition also showed the best electrocatalytic performance for glycerol.