Journal of Power Sources, Vol.195, No.19, 6323-6328, 2010
Stable support based on highly graphitic carbon xerogel for proton exchange membrane fuel cells
Highly graphitic carbon xerogel (GCX) is prepared by the modified sol-gel polymerization process using cobalt nitrate as the catalyst, followed by high temperature treatment at 1800 degrees C. The as-prepared GCX is explored as a stable support for Pt in proton exchange membrane fuel cells. The results of N-2 sorption measurement and X-ray diffraction analysis (XRD) reveal that GCX has a better mesoporous structure and a preferably higher degree of graphitization, compared with the commercial XC-72 carbon black. The transmission electron microscopy (TEM) image indicates that Pt nanoparticles are well dispersed on GCX and exhibit relatively narrow size distribution. Accelerated aging test (AAT) based on potential cycling is used to investigate the durability of the as-prepared Pt/GCX in comparison with the commercial Pt/C. Electrochemical analysis demonstrates that the catalyst with GCX as a support exhibits an alleviated degradation rate of electrochemical active surface area (39% for Pt/GCX and 53% for Pt/C). The results of single cell durability tests indicate that the voltage loss of Pt/GCX at 100 mA cm(-2) is about 50% lower than that of Pt/C. GCX is expected to be a corrosion resistant electrocatalyst support. (C) 2010 Elsevier B.V. All rights reserved.
Keywords:Proton exchange membrane fuel cells;Carbon xerogel;Carbon support;Durability;Accelerated aging test