Acta Phys. -Chim. Sin. ›› 2013, Vol. 29 ›› Issue (08): 1753-1761.doi: 10.3866/PKU.WHXB201306141

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

Electrochemical Behavior of Pyridine-Doped Carbon-Supported Co-Phthalocyanine (Py-CoPc/C) for Oxygen Reduction Reaction and Its Application to Fuel Cell

DAI Xian-Feng1, ZHEN Ming-Fu2, XU Pan1, SHI Jing-Jing1, MA Cheng-Yu1, QIAO Jin-Li1   

  1. 1 College of Environmental Science and Engineering, Donghua University, Shanghai 201620;
    2 Zhejiang Geely Automotive CO.,LTD, Shanghai 201501
  • Received:2013-04-01 Revised:2013-06-07 Published:2013-07-09
  • Contact: QIAO Jin-Li E-mail:qiaojl@dhu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21173039), Specialized Research Fund for the Doctoral Program of Higher Education, China (20110075110001), and Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, China (20110927) .

Abstract:

Pyridine-doped, carbon-supported Co-phthalocyanine (Py-CoPc/C) nanoparticle catalysts were synthesized via a combined solvent-impregnation and milling procedure, using Co-phthalocyanine (CoPc) and pyridine (Py) as the catalyst precursors. The morphologies and compositions of the catalysts were characterized using X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), and X-ray photoelectron spectroscopy (XPS). The electrocatalytic activities and stabilities were evaluated by linear sweep voltammetry (LSV), using a rotating disk electrode technique, in terms of their oxygen reduction reaction (ORR) activity as a function of Py doping. The results show that Py doping can significantly improve the catalytic activity of CoPc/C toward the ORR, and the optimal Py doping level is around 20% (i.e., 20%Py-20%CoPc/C), for which an onset potential of 0.20 V (vs SHE) and a half-wave potential of -0.03 V were achieved in 0.1 mol·L-1 KOH electrolyte. Compared with 40%Py/C and the 40%CoPc/C catalyst, the half-wave potential on the 20%Py-20%CoPc/C catalyst for the ORR shifted positively by 160 mV and 15 mV, respectively. The number of electrons transferred for the ORR also increased from 1.96 to 2.38, indicating an enhancement in ORR selectivity. Scanning electron microscopy-EDX and XRD analysis revealed that the N mass fraction (w) and dispersion of CoPc on carbon are improved by Py doping, which improves adsorption of O2 molecules on the catalyst surfaces. XPS analysis clearly showed pyridinic-N and graphitic-N in the Py-CoPc/C catalysts. Both are believed to be coordinated to Co ions on the catalyst surfaces, and this might be responsible for the enhanced ORR activity. An H2/O2 fuel cell using membrance electrode assembly (MEA), fabricated with a 20%Py-20%CoPc/ C cathode catalyst, generated a peak power density of 21 mW·cm-1, which is 2.4 times that of CoPc/C under the same operating conditions.

Key words: Carbon supported Co-phthalocyanine, Pyridine-doping, Oxygen reduction reaction, Membrane electrode assembly, H2-O2 single cell

MSC2000: 

  • O643