In this work, we studied the characteristic variations of catalyst supports caused by mechanical milling and their electrochemical application in fuel cells. Two different catalyst supports, carbon black (XC-72R) and K20 (mesoporous carbon), were crushed anti dispersed by mechanical milling using a bead mill. The bead mill operated with 0.3 mu m zirconia beads at the rate of 3500 rpm for 30 min. The secondary particle size of the crushed catalyst supports ranged from around 0.1 pm to 10 mu m. The secondary particle size of the catalyst supports after crushing represents a decrease of approximately 10% compared with that of raw catalyst supports. To confirm the role of the catalyst supports in the direct methanol fuel cell (DMFC), Pt and Ru were loaded onto these catalyst supports using an impregnation method. In the single cell test, Pt-Ru/XC-Bead and PtRu/K20-Bead showed power densities of 135 mW/cm(2) and 144 mW/cm(2) under air at 60 degrees C, respectively. The performance values of these catalysts, which were fabricated using reformed catalyst supports, were 10% to 20% higher than those of raw catalyst supports. As a result, the catalyst supports crushed by the bead mill helped to improve the electrochemical performance of the direct methanol fuel cell. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.