Tuning the catalytic activity of Ag(110) supported Fe-phthalocyanine in the oxygen reduction reaction

A careful choice of the surface coverage of Fe-phthalocyanine (FePc) on Ag (110) around the single monolayer allows us to drive with high precision both the long-range supramolecular arrangement and the local adsorption geometry of FePc molecules on the given surface.We show that this opens up the possibility of sharply switching the catalytic activity of FePc in the oxygen reduction reaction in a reproducible way. F. Sedona, et al. http://www.nature.com/nmat/journal/v11/n11/pdf/nmat3453.pdf

A combination of different techniques such as Scanning Tunneling Microscopy, synchrotron radiation X-ray photoelectron and absorption spectroscopy combined with density functional theory (DFT) calculations shows that the molecular local chemisorption site and the long-range supramolecular arrangement of Metallo-Phthalocyanine molecules in the monolayer coverage range on a metal surface can be controlled by fine tuning of the overlayer coverage. This in turn opens the possibility of reliably mastering adsorption-site-selective properties such as the molecular catalytic activity, as will be shown here with respect to the FePc-catalysed oxygen reduction reaction, which can be reproducibly switched on or quenched by controlling the Fe-Phthalocyanine local adsorption site in the single-ML range. Our claims are substantiated by characterizing the molecular coordination in the catalytically active phase in the presence of oxygen and by checking that the Fe-Phthalocyanine molecules remain intact throughout the catalytic cycle. Finally, we show that the catalyst pushes the Ag support oxidation to levels unattainable in ultra high vacuum by dosing oxygen on clean silver single-crystal surfaces, and that reduced oxygen thus formed can be fully removed by providing hydrogen ions to the interface.

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Tuning the catalytic activity of Ag(110) supported Fe phthalocyanine in the oxygen reduction reaction, F. Sedona, M. Di Marino, D. Forrer, A. Vittadini, M. Casarin, A. Cossaro, L. Floreano, A. Verdini and M. Sambi
http://www.nature.com/nmat/journal/v11/n11/pdf/nmat3453.pdf
Ultima modifica il Lunedì, 18 Novembre 2013 15:44