The size-controlled Pt/C/PTFE hydrophobic catalyst pellets employed in the hydrogen-water isotope exchange reaction were prepared using microfluidic technology. An assembly-disassembly capillary-based microfluidic system was demonstrated for easy fabrication of narrow size-distribution catalyst beads (CV < 5%), and the size of the beads were precisely controlled in the range of 150-1500 mu m by manipulating the flow rate of the disperse and continuous phase, as well as the continuous phase viscosity. Approximately 3 nm platinum nanoparticles with uniform dispersion in a porous PTFE/C support were synthesized by gamma-ray-induced reduction without using any chemical reducing agents. Polyvinyl alcohol (PVA) was introduced as both a solidified agent and porogen in the fabrication process. The porosity of the as-prepared catalyst pellets were characterized using a scanning electron microscope (SEM) and a BET instrument, and the hydrophobicity of the catalyst was examined by observation of the contact angle between water and the surface of the catalyst beads. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.