Calcined Co(II)-Chelated Polyazomethine as Cathode Catalyst of Anion Exchange Membrane Fuel Cells

• Published in: Polymers Vol. 14; no. 9; p. 1784
• Main Authors: Cheng, Yu-Wei, Hsieh, Tar-Hwa, Huang, Yu-Chang, Tseng, Po-Hao, Wang, Yen-Zen, Ho, Ko-Shan, Huang, Yue-Jie
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 27.04.2022; MDPI
• Subjects: Acid leaching; Alcohol; anion exchange membrane fuel cell; Anion exchanging; Carbon; Catalysts; cathode catalyst; Cathodes; Chemical reduction; Diamines; Electrode polarization; Electrodes; Fourier transforms; Fuel cells; High resolution electron microscopy; Hot pressing; Membranes; Metals; Microscopy; Nitrogen; oxygen reduction reaction; Oxygen reduction reactions; Phenylenediamine; polyazomethine; Polyazomethines; Polymerization; Polymers; Pore size; Raman spectroscopy; Roasting; Spectrum analysis; X ray photoelectron spectroscopy; United States > US; Japan; Germany; anion exchange membrane fuel cell; polyazomethine; oxygen reduction reaction; cathode catalyst
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym14091784

Polyazomethine (PAM) prepared from the polycondensation between p-phenylene diamine (PDA) and p-terephthalaldehyde (PTAl) via Schiff reaction can physically crosslink (complex) with Co ions. Co-complexed PAM (Co-PAM) in the form of gel is calcined to become a Co, N-co-doped carbonaceous matrix (Co-N-C), acting as cathode catalyst of an anion exchange membrane fuel cell (AEMFC). The obtained Co-N-C catalyst demonstrates a single-atom structure with active Co centers seen under the high-resolution transmission electron microscopy (HRTEM). The Co-N-C catalysts are also characterized by XRD, SEM, TEM, XPS, BET, and Raman spectroscopy. The Co-N-C catalysts demonstrate oxygen reduction reaction (ORR) activity in the KOH(aq) by expressing an onset potential of 1.19-1.37 V vs. RHE, a half wave potential of 0.70-0.92 V, a Tafel slope of 61-89 mV/dec., and number of exchange electrons of 2.48-3.79. Significant ORR peaks appear in the current-voltage (CV) polarization curves for the Co-N-C catalysts that experience two-stage calcination higher than 900 °C, followed by double acid leaching (CoNC-1000A-900A). The reduction current of CoNC-1000A-900A is comparable to that of commercial Pt-implanted carbon (Pt/C), and the max power density of the single cell using CoNC-1000A-900A as cathode catalyst reaches 275 mW cm .