Designed Synthesis Of Element-doped Carbon Materials Support Noble Matel Electrocatalysts And Its Performance Investigation

As a new type of green energy,direct alcohol fuel cell is highly efficient and environmental friendly,being able to meet the requirements of energy and environment.However,the electrocatalytic activity of anode is lower,which is the main obstacle.The development of efficient anode catalysts is the key to solve this problem.At present,the main anode catalyst is Pt / C,whichis precious metal.However,the price of precious metals is expensive because of their limited reserves on the earth,which hampered the commercialization of this catalysts.There are two ways to solve this problem: First,we can alloy the precious metal and other metals,which can reduce the amount of precious metals while maintaining the catalytic activity.Second,we can select the appropriate support materials,improving the dispersion of precious metals,thereby enhancing the utilization of noble metals.In order to reduce the amount of precious metals and improve the activity of the catalyst,a new type of anodic catalyst with high electrocatalytic activity,simple preparation process and low cost was prepared by optimizing the alloy composition and developing the new carrier.A series of novel composite catalysts were synthesized by using a heterogeneous element-doped carbon material as the supporting materails and supporting the noble metal alloy with special structure.The main contents of this paper were summarized as follows:Firstly,we synthesized nitrogen-doped grapheme using the pyrrole as nitrogen source.The platinum-copper trigonal bipyramid composite catalyst was synthesized by template-free method,with the nitrogen-doped graphe as support materials and chloroplatinic acid and copper chloride as metal precursors.Their morphology and structure were characterized by HR-TEM,SEM,FESEM,Mapping,XRD and XPS.The nitrogen atom had been doped on the graphene successfully.The nitrogen doping typeswere mainly pyridine and graphite type.The PtCu trigonal bipyramid was multi-stage structure.The dendrite size of the trigonal bipyramid was about 5-20 nm and the average particle is about 100 nm.It dispersed well on the nitrogen-doped graphene.Electrochemical measurements demonstrated that this T-PtCu / NG catalyst could have high catalytic activity for the electrochemical oxidation of ethylene glycol,and good anti-CO poisoning ability.Secondly,the sulfur-doped grapheme was synthesized by using the thiophene as sulfur source.And the ratio of metal precursors was changed to synthesize sulfur-doped graphene-supported platinum-copper flake composite catalyst.The results showed that the sulfur atoms had been doped on graphene successfully.The sulfur dopingtype is mainly thiophene and graphite sulfur type.The platinum copper flake average particle was about 10-25 nm.Meanwhile it dispersed well on the sulfur-doped graphite.Electrochemical characterization showed that the composite catalyst F-PtCu / SG had excellent catalytic activity and stability for alcohol oxidation.Thirdly,the sulfur-doped graphite was synthesized by using the thiophene as sulfur source.We synthesized sulfur-doped grapheme supported palladium-copper alloy cubic catalyst by template-free method.And we systematically studied the effect of different element doping on the morphology and electrical properties.The results showed that the prepared palladium-copper alloy cubic(about 50 nm in diameter)can be uniform dispersed on the surface of the sulfur-doped graphene.Electrochemical characterization showed that H-PdCu / SG catalyst for alcohols oxidation had higher electrocatalytic activity than H-PtCu / NG and H-PtCu / G.Fourthly,the cobalt and nitrogen co-doped carbon materials(Co-N-C)with double-shell structure were controlled by template-free method using melamine and formaldehyde as the nitrogen and carbon sources,and the cobalt acetate as the metal precursor.We used it as a supporter loaded the palladium-copper alloy cubic catalyst.Moreover we studied the electrical properties of the catalyst for the electrocatalytic oxidation of alcohols.The morphology and structure of the materials were characterized by SEM,TEM,XRD and XPS.The electrocatalytic activity of the catalysts was discussed by cyclic voltammetry(CV),chronoamperometry(I-T)and active surface area.The results showed that the Co-N-C had a large specific surface area,resulting of better contact with the Pd-Cu alloy catalyst particles.The electrochemical test results showed the catalyst has good electrocatalytic activity and lasting stability.In order to improve the catalytic activity of the anode catalyst,we synthesized a series ofnew nano-assembly material with special morphology using the doped carbon material as the carrier loaded the noble metal alloy which effectively improved the direct alcohol fuel cell electrocatalytic activity and stability of anode catalysts.At the same time,we studied the effectsof carrier and metal alloying on catalysts activity through scientific characterization methods.