Herein we present a simple one-step method to produce polyelectrolyte-capped Pt nanoparticles able to be assembled into layer-by-layer arrays with a linear dependence of the amount of deposited material on the number of dipping cycles. The resulting supramolecular films where fully characterized by AFM, XPS and ATR-FTIR. The electrochemical evaluation by cyclic voltammetry showed good electrochemical connection between the nanoparticles in both acidic and neutral solutions. The films assembled on graphite electrodes showed catalysis of the H-2 production and the interconnection between nanoparticles proved to be effective up to 20 bilayers. Results presented here reveal an easy procedure to obtain stable arrays of well-dispersed electroactive 2 nm-diameter Pt nanoparticles on a variety of substrates with direct potential applications in energy conversion devices. (C) 2017 Elsevier B.V. All rights reserved.