Synthesis And Characterization Of Electrocatalysts Based On Metal Supramolecular Complexes

Fuel cell has become the focus of the research work in recent years because of its high energy conversion efficiency and cleanness.The focus of the present research is mainly on the highly efficient cathode catalysts and electrocatalysis materials.The stability and high price factors of catalytic materials have seriously restricted the practicability of high-power fuel cell,especially for the normal temperature battery,and hinder the marketization of fuel cell.Therefore,developing new ideas,designing new materials cathodic catalysts which have low cost,high catalytic activity and high stability are the trend of basic research of fuel cells.Metal supramolecular complexes have shown N excellent properties as electrocatalysts in recent years.In this paper,four kinds of metal supramolecular complexes were synthesized and the catalysts were determined by physical and electrochemical characterization.(1)We synthesized the nitrogen rich precursors(BTPHC)by chemical reaction.Then BTPHC precursor metal complexes were synthesized by reaction of precursor and copper containing copper perchlorate.Firstly,the synthesis of catalyst precursor and the successful coordination of metal were proved by HEM,FTIR and UV tests.Then the catalytic performance was tested by electrochemical tests including CV,RDE and RRDE,meanwhile compared with commercialized Pt/C.The final result shows that the reduction process of Cu-BTPHC/C catalyst for oxygen is four electron transfer pathway,which directly transforms oxygen into water.Although the catalytic performance of Cu-BTPHC/C is lower than Pt/C,it has its own advantages.(2)The supermolecular complex Cu-HFBPT of tripline was synthesized by chemical synthesis.The catalyst synthesis was also confirmed by the physical characterization method.According to the TGA test,we can infer that the catalyst precursor HFBPT had good thermal stability.According to the electrochemical test of the catalyst,it is found that the catalytic activity of the catalyst is better than that of the carbon powder.Although the performance is no more than Pt/C,it has shown its own merits in the production of hydrogen peroxide.(3)The precursor of Cu-NPPA/C was synthesized from 2,6-Pyridinedicarbonyl dichloride and 1,10-phenanthroline-5-amino group by chemical synthesis.Then the precursor was complexed with copper ions to form Cu-NPPA/C.A series of physical characterizations(SEM,XPS)and electrochemical tests(CV,RDE,RRDE)were carried out after the adhesion of the catalyst with the carbon powder.Finally,the following conclusion is obtained: Cu-NPPA/C is a ORR reaction through four electron transfer pathways,and the content of hydrogen peroxide is very small.However,by the thermal weight analysis,the reaction must be carried out at a lower temperature,because the thermal stability of the precursor is poor.(4)1,2,4,5-Benzenetetramine tetrahydrochloride and 1,10-Phenanthroline-5,6-dione Chemical reaction was used to synthesize the nitrogen precursor L1.Then L1 was combined with metal ions,and then the carbon powder was added to get the powder of carbon supported metal supramolecular complex.We marked it as Cu-L1/C.The difference is that the catalyst is directly attached to the carbon powder directly under the liquid environment compared with the aboved.The result shows that this will make the carbon powder on the surface of the carbon powder more uniform.Therefore,Cu-NPPA/C has the following advantages: the overpotential is decreased,the half wave potential is larger,the content of hydrogen peroxide is smaller,and it tends to 4 electron reaction.