In this study, we present an easy way for catalyst (Pt/ACFs) production. All processes associated with formation of stable particles, i.e. reaction reduction, nucleation, growth and their subsequent deposition on active carbon fibers were carried out in one microreactor cycle. It was shown, that using some results from kinetic study, it is possible to predict time, where polyvinyl alcohol as stabilizer should be added to the reacting mixture (Pt(IV) ions with sodium borohydride). As results, we obtained stable platinum nanoparticles with radius size varied from 5.0 +/- 3.0 nm for total flow rate equal to 2.0 mL/min to 3.5 +/- 1.5 nm for 4.0 mL/min, which were successfully deposited on active carbon fibers with efficiency from about 81%-95%, respectively. (C) 2013 Elsevier B.V. All rights reserved.