The corrosion resistance of carbon black, carbon nanofiber and carbon nanocage used as catalyst supports in fuel cells was investigated by monitoring CO2 emission using on-line mass spectrometry when 1.4 V was applied for 30 min. The changes associated with the carbon corrosion were assessed through electrochemical methods. In general, graphitized carbon supports were more corrosion-resistant than amorphous carbon black. However, the degree of graphitization did not directly correlate with higher resistance to corrosion. Hydrophobicity was critical in enhancing resistance to corrosion. When sintering of Pt particles was considered, carbon nanocages were more resistant than nanofibers. The present findings thus indicate that the carbon nanocage is an appropriate catalyst support in fuel cell systems. (C) 2009 Elsevier Ltd. All rights reserved.