Supramolecular Films of Highly-Connected Pt Nanoparticles for Electrocatalysis of Hydrogen Production

GONZALO E. FENOY; WALDEMAR A. MARMISOLLÉ; OMAR AZZARONI

Buenos Aires

Congreso; Frontiers in Physical Sciences Humboldt Kolleg; 2016

ICAS-UnSAM

Metal nanoparticles (NPs) become a remarkable alternative to the usage of massive noble metals in electrochemical applications as they offer large surface areas even for low metal load, keeping (or even enhancing) the electrocatalytic properties of the metal. NPs need to be supported on the electrode surface and the control of composition and morphology of the electrochemical interfaces is an essential aspect of the design of electrochemical devices. In this work, 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 spectroscopic studies indicate that the film growing up is homogenous and almost complete charge neutralization occurs between the polyelectrolyte components due to the low ionic strength of the solutions employed for assembly. This allows an interdigitation of the assembled layers that produces an intimate contact of the metallic nanoparticles across the film, increasing the electrical connectivity. 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.