Pt-based nanomaterials as catalysts platforms

A. FLORIDIA ADDATO; EUGENIA ZELAYA; A.A. RUBERT; G. BENITEZ; M. FONTICELLI; R. C. SALVAREZZA

San José

Conferencia; Pan-American Advanced Studies Institute on Scalable, Functional Nanomaterials; 2011

Johns Hopkins University

Size and morphology of Pt nanoparticles (NPs), and their distribution on the appropriate support, are the most important variables that control catalytic activity. Colloidal synthesis of NPs, in particular those methods involving the use of alkanethiols as stabilizing agents, provide a way for making monodispersed nanomaterials. Furthermore, thiol-capped Pt NPs are of great interest due to the effect that adsorbed sulfur might have on their electronic properties. Enhacement of the catalytic activity can be achieved by dispersing the NPs on high surface area supporting materials, such as carbon substrates. This work involves the study of different systems behaviour ranged from smooth and nanostructured substrates to metallic nanoparticles. In particular, we have studied alkanethiol adsorption on polycrystalline Pt and the electrochemical stability of the resulting SAMs. This also included the preparation and characterization of the Pt substrates. We have focussed on the synthesis of Pt nanoparticles, using thiols as stabilizing agents. In a tentative route for the development of a catalyst, the second step corresponds to the selection of the appropriate supporting material. We have dispersed the nanoparticles on carbon susbstrates (planar graphite and Vulcan XC72R). We study the catalytic activity of these materials considering the effect that might cause the presence of sulfur in the surface. Since size and morphology deeply matter on catalytic activity, morphological studies of the nanoparticles have been performed by High-Resolution Transmission Electron Microscopy.