Preparation, Characterization And Application Of Polymer-based Non-noble Metal Oxygen Reduction Catalysts

Now fuel cells have been considered as one of the most promising energy conversion devices due to its high power density and conversion efficiency, quick start-up and environmental-friendly nature. However, many problems hindered its commercialization which are high costs and difficult preparation of electrocatalysts used in cathode. So it is essential to find new, available, effective, none-noble electrocatalysts for oxygen reduction reaction(ORR). In this paper, we prepared a series of transition-metal-coordinating nitrogen-doped carbon catalyst(M-N/C). The electrochemical performances of these catalysts were characterized by CV(cyclic voltammetry), RDE(rotating disk electrode), RRDE(rotating ring-disk electrode) and EIS(electrochemical impedance spectroscopy) techniques while the morphologies and chemical compositions of catalysts were studied by SEM(scanning electron microscopy) and XPS(X-ray photoelectron spectroscopy) methods.1. Two new none-precious metal electrocatalysts for the reduction of oxygen(ORR) were prepared by a facile method, which is characterized by the sequential procedure including oxidation polymerization, chemical coupling and ion complexation reactions etc. The carbon supported poly(indole-6-carboxylic acid) composite(PIn/C) was obtained by the in-situ polymerization method, which was linked with 5-amine-1,10-phenanthroline to form the PInPhen/C composite, and the final CuPInPhen/C or FePInPhen/C catalysts were obtained by the complexation reaction of PInPhen/C with Cu(II) or Fe(II) ions. It is found that both of two catalysts can reduce oxygen by a predominant four-electron pathway.2. A novel metal-phenanthroline compound synthesized on the basis of conducting polymer was used as electrocatalyst for ORR. At first the conducting monomer BTPP(10,12-bis(4-butylthiophen-2-yl)thieno[3’,4’:5,6]pyrazino[2,3-f][1,10]phenanthroline) material was prepared by bonding with 2,5-dibromo-3,4-dinitrothiophene and 4,4’’-dibutyl-[2,2’:5’,2’’-terthiophene]-3’,4’-diamine to study electrochemical properties when the polymer(PBTPP) demonstrated low power density and negative potential in 0.1M PBS solution. Thus we complexed copper(II) with PBTPP to obtain a new metal-phenanthroline catalyst Cu-PBTPP which exhibit a better ORR activity and stability, indicating the metal cation plays a key role to enhance the electrocatalytic activity.3. We described the synthesis and assessment of a non-noble-metal electrocatalyst for ORR. The transition-metal-coordinating nitrogen-doped carbon catalyst(M-N/C) was prepared by supporting copper iron on carbon-coated PDTPP poly(2,7-dimethyl-10,12-di(thiophen-2-yl)thieno[3’,4’:5,6]pyrazino[2,3-f][1,10]phenanthro line) complex to offer Cu-PDTPP/C. And Cu-PDTPP/C showed an excellent current density and onset potential than PDTPP, PDTPP/C, Cu-PDTPP which illustrated the electrochemical mechanism of copper coordination carbon catalysts are superior to other ones without metal ions and carbon carriers.4. We demonstrated in-situ synthesis of one novel imidazolidine Schiff base copper complex as electrocatalysts for ORR in 0.1 M KOH media. The electrocatalyst was prepared by the reaction of salicylaldehyde, tetraethylenepentamine(TEPA) and copper perchlorate in-situ yields a novel Schiff base complex [Cu2(L)]2(ClO4)2 CH3CN(H2O)4. And the copper complex can be used as highly efficient electrocatalysts which exhibited a predominant four-electron pathway during oxygen reduction reaction.