Catálogo de Investigaciones | 2011-2012

139 Catálogo de Investigaciones | Pontificia Universidad Católica de Puerto Rico Electrochemical Reactivity of Aromatic Molecules at Nanometer- Sized Surface Domains: From Pt(hkl) Single Crystal Electrodes to Preferentially Oriented Platinum Nanoparticles This presentation will compare the electrochemically controlled adsorption of hydroquinone-derived adlayers and their reductive desorption from nanometer-sized Pt(111) domains present on the surface (i) of model stepped single-crystal electrodes and (ii) of preferentially oriented Pt nanoparticles. The results obtained using a stepped surface series, i.e., Pt(S) [(n−1)(111)×(110)], suggest that in the presence of 2 mM H 2 Q (aq) the electrochemically detected desorption-adsorption process takes place selectively from ordered Pt(111) domains present as terraces, while being precluded at other available surface sites, i.e., Pt(110) steps, where adsorption takes place irreversibly. This domain-selective electroanalytical detection scheme is employed later to selectively monitor desorption-adsorption of hydroquinone-derived adlayers from ordered, nanometer- scaled Pt(111) domains on the surface of preferentially oriented Pt nanoparticles, confirming the existence of well-ordered (111) domains on the surface of the Pt nanoparticles. A good correlation is noted between the electrochemical behavior at well-ordered Pt(hkl) surfaces and at preferentially oriented Pt nanoparticles. Key learnings and potential applications are discussed. The results demonstrate the technical feasibility of performing domain-selective decapping of nanoparticles by handle of an externally controlled parameter, i.e., the applied potential. dra. margarita rodríguez-lópez mentor dr. juan m. feliú co-director dr. arnaldo carrasquillo, jr. colaboradores josé solla-grullón, enrique herrero, paulino tuñón y antonio aldaz aromatic molecules adsorption/desorpton process supramolecular interactions