The Synthesis And Performance Of Copper-manganese Co-doped Carbon-Based Catalysts For Oxygen Reduction Reaction

Owing to global economic and social development,energy crisis and air pollution is growing worse.It's very important for human to develop new clean energy power technologies.Among these new technologies,fuel cells have attracted people's attention.Platinum-based electrocatalysts are the main catalysts for oxygen reduction reaction(ORR).It is infrequent and costly and has become an obstacle for the largescale application of fuel cell technologies.Therefore,it is meaningful to develop efficient non-noble metal catalysts to replace the precious metal materials for ORR.Many non-noble metal electrocatalysts have been synthesized in recent years,but their catalytic activity is still far from being satisfactory or adequate.Among various non-noble metal ORR catalysts,bimetallic doped carbon-based materials show good ORR catalytic activity.Especially,Cu and Mn co-doped materials show a greater potential for catalyzing ORR.It's of great significance to design and synthesize Cu and Mn co-doped carbon-based materials with highly effective ORR catalytic activity.Herein,the Cu,Mn co-doped carbon-based ORR catalysts were prepared and systematically studied for their morphology features,structure,constitution and catalytic activity.The main research results are as follows:1.Copper-manganese co-doped carbon-based catalyst(Cu-Mn-N-C)was prepared by physical grinding and pyrolysis of the mixture copper-o-phenylenediamine and manganese-o-phenylenediamine and silica pellets.The Cu-Mn-N-C material has rich mesoporous structure,large specific surface area,high degree of graphitization,and high-density Cu-Nx and Mn-Nx active sites.These characteristics efficiently improve the ORR catalytic activity of Cu-Mn-N-C.The ORR half-wave potential over Cu-MnN-C reach up to 0.86 V,is 20 mV higher than that over the commercial Pt/C,and exceeding those over the similar Cu-doped or Mn-doped ORR catalysts reported in the literature.2.The Copper-manganese co-doped graphene nanosheets catalysts(Cu-Mn-N-GR-n)were obtained by twice thermal treatment method using the mixture of coppero-phenanthroline and manganese-o-phenanthroline complexes and montmorillonite as the precursor.Cu-Mn-N-GR-n has some special characteristics,such as large specific surface area and rich pore structure,high degree of graphitization,abundant Cu-Nx and Mn-Nx structural units on the surface of Cu-Mn-N-GR-n,which is beneficial to increase the electron and mass transport capacity in the ORR process and active site density on the surface of the catalysts.The half-wave potential of oxygen reduction reaction on the Cu-Mn-N-GR-n is 60 mV higher than that on Pt / C.In addition,the catalytic activity of Cu-Mn-N-GR-n is superior to the non-noble metal doped carbonbased ORR catalyst reported in the literature.3.Mesoporous manganese-nitrogen-carbon supported nano copper metal material(Cu @ Mn-N-C)was prepared by thermal conversion using mesoporous manganesenitrogen-carbon as support.The prepared Cu @ Mn-N-C materials exhibit rich pore structure,high specific surface area,plenty of structural units of N-C and Mn-N,large degree of graphitization and uniformly dispersed Cu nanoparticles,which is the material foundation of the excellent catalytic performance.In 0.1 M KOH,Cu @ MnN-C exhibited excellent ORR catalytic activity.The half-wave potential of ORR on Cu @ Mn-N-C was 20 mV higher than that on commercial Pt / C,and it was superior to those on the similar Cu-loaded ORR catalysts reported in the literature.As indicated above,it can be seen that the Cu and Mn co-doped carbon-based nonnoble metal catalysts show excellent catalytic activity and stability,and have broad application prospects.