American Chemical Society, ACS Applied Materials and Interfaces, 49(8), p. 33690-33696, 2016
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Pt nanoparticles (NPs) strongly grafted on few layers graphene (G) have been prepared by pyrolysis under inert atmosphere at 900 ºC of chitosan films (70-120 nm thickness) containing adsorbed H2PtCl6. Preferential orientation of exposed Pt facets was assessed by XRD of films having high Pt loading in where the 111 and 222 diffraction lines were observed and also by SEM imaging comparing elemental Pt mapping with the image of the 111 oriented particles. Characterization techniques allow to determine the Pt content (from 45 ng to 1 µg cm-2, depending on the preparation conditions), particle size distribution (9±2 nm) and thickness of the films (12-20 nm). Oriented Pt NPs on G exhibit at least two orders of magnitude higher catalytic activity for aqueous phase reforming of ethylene glycol to H2 and CO2 than analogous samples of randomly oriented Pt NPs supported on preformed graphene. Oriented (Pt) ̅/fl-G undergoes deactivation upon reuse, the most probable cause being Pt particle growth, probably due to the presence of high concentrations of carboxylic acids acting as mobilising agents during the course of the reaction.