High durability fuel cell cathodes obtained from cobalt metal organic frameworks

ANA KATHERINE DíAZ-DURAN, FEDERICO A. VIVA, FEDERICO RONCAROLI; ANA KATHERINE DíAZ-DURAN, FEDERICO A. VIVA, FEDERICO RONCAROLI

ELECTROCHIMICA ACTA

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2019 vol. 320

0013-4686

Mesoporous carbonsdoped with Nitrogen and Cobalt were obtained from the pyrolysis of two differentCobalt Metal-Organic Frameworks (MOFs, ZIF-67 and CoNic) and from one linearcoordination polymer (CP, Co(CO2)2Pz). (ZIF-67 = catena-(bis(ì2-2-methylimidazolato)-cobalt(II),CoNic = catena-(bis(ì3-nicotinato)-bis(ì2-nicotinato)-(ì2-aqua)-di-cobalt(II),Co(CO2)2Pz = catena-((ì2-pyrazine-2,3-dicarboxylato)-diaqua-cobalt(II)dehydrate).   The carbonization productswere evaluated as cathode catalysts in polymer electrolyte membrane fuel cell(PEMFC). Membrane Electrode Assemblies (MEAs) prepared with the Co-N dopedcarbons and Pt 20 % supported on Vulcan carbon as anode catalyst, werecharacterized in a PEMFC and post mortemby SEM, EDX, XPS and X-ray diffraction. The best catalyst was the one derivedfrom the Co(CO2)2Pz polymer, pyrolyzed at 700 oCand acid leached. It reached a maximum power density of 259 mW cm-2,a limiting current of 1.36 A cm-2 and an open cell voltage of 0.86V. These parameters are comparable to those of Pt 20 % on Vulcan. The fuel cellprototype constructed with the Co(CO2)2Pz 700 oCmaterial was able to operate for 500 hours, without significant change of itselectrochemical parameters and without leaking Co or Pt.