| The metal-air fuel cells are very promising power source and they have high theoretical voltage, high energy density, low cost, light weight, and environmental compatibility. The air cathode is the main determinant of the oxygen reduction reaction (ORR). Thus, a metal-air fuel cell performance is mainly determined by the cathode catalyst.The catalytic activity of monomer porphyrin has relatively poor stability and we designed and synthesized polymeric metalloporphyrin (PTPPM) on this basis with new technology. IR and UV spectra are used to characterize the structure of PTPPM. Results confirmed that the synthesized product was target compounds. Combined differential thermal analysis and UV spectroscopy, the thermal stability of the porphyrin was tested, and the results show that PTPPM did not decompose below600℃. The catalyst with different activation temperature and different loading of MN4were explored and the best activation temperature and loading of MN4were600℃and6wt%respectively. The initial reduction potential of PTPPPt/C and PTPPPd/C under acidic conditions was0.85,0.84V vs. RHE respectively. The number of electrons transferred was3.85and3.83. The morphology, microstructures and valence of the catalyst were characterized by TEM, XRD and XPS. The results show that PTPPM with HT of600℃loads evenly to the surface of carbon. The catalyst is an amorphous structure, and the catalytic activity of the metal center of the porphyrin ring was metal ions.The loading of MN4in catalyst layer was lmg/cm2. The air electrode and metal-air fuel cells with different catalysts were researched. From the results of discharge cures, the performance of PTPPM/C catalyst was close to the Pt/C catalyst, but much berrer than TPPFe/C catalyst. Continuous discharge at a constant current for500min of the metal-air fuel cells was hardly attenuated. PTPPM/C catalyst for metal-air fuel cells had a stable discharge performance. |
