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

Yu-Wei Cheng; Tar-Hwa Hsieh; Yu-Chang Huang; Po-Hao Tseng; Yen-Zen Wang; Ko-Shan Ho; Yue-Jie Huang

doi:10.3390/polym14091784

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

Polymers (Basel). 2022 Apr 27;14(9):1784. doi: 10.3390/polym14091784.

Authors

Yu-Wei Cheng¹, Tar-Hwa Hsieh², Yu-Chang Huang², Po-Hao Tseng³, Yen-Zen Wang⁴, Ko-Shan Ho², Yue-Jie Huang²

Affiliations

¹ Department of Chemical Engineering, Ming Chi University of Technology, New Taipei City 243303, Taiwan.
² Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, 415, Chien-Kuo Road, Kaohsiung 80782, Taiwan.
³ Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan.
⁴ Department of Chemical and Materials Engineering, National Yu-Lin University of Science & Technology, 123, Sec. 3, University Road, Dou-Liu City, Yun-Lin 64301, Taiwan.

Abstract

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^-2.

Keywords: anion exchange membrane fuel cell; cathode catalyst; oxygen reduction reaction; polyazomethine.

Grants and funding

This research received funding from MOST 108-2221-E-992-037 and MOST 109-2221-E-992-083 through the Minister of Science and Technology, Taiwan, ROC.