CO chemisorption at vacancies of supported graphene films: a candidate for a sensor?

We investigate CO adsorption at single vacancies of graphene supported on Ni(111) and polycrystalline Cu. The borders of the vacancies are chemically inert but, on the reactive Ni(111) substrate, CO intercalation occurs. Adsorbed CO dissociates at 380 K, leading to carbide formation and mending of the vacancies, thus preventing their effectiveness in sensor applications

Chemical Reactivity And Electronical Properties Of Graphene And Reduced Graphene Oxide On Different Substrates

The chemical reactivity and the electronical properties variation of graphene (G) supported on Ni(111) and of the reduced Graphene Oxide (rGO) will be described thanks to the framework of University of Genoa and Polytechnic of Turin. We will present the main results obtained on the reactivity, towards CO, of pristine graphene grown on Ni(111). Single layer graphene films are grown by ethene dehydrogenation on Nickel, under different experimental conditions, and the system is studied in-situ by X-ray Photoemission and High-Resolution Electron Energy Loss Spectroscopies before and after CO exposure at 87 K and at room temperature. The main results were: - the best CO reactivity in the top-fcc configuration [1] of graphene on Ni(111), at low temperature [2] - the higher reactivity occurs in the case of minimum percentage of contaminant or Ni2C still present during the grown process. - a reactivity toward CO at room temperature on graphene with punctual controlled defects by sputtering, with possible applications e.g., gas sensing [3, 4]. More applicative aspect is the modification of GO in rGO, by UV based process. During the reduction, electrical properties is improved, opening possible application in the ink-jet printing mechanism as conductive printing system, coating or in the functionalization [5] of G

Crackling noise peaks as signature of avalanche correlation

Until now, all existing theories failed to explain peaks in the power noise spectra. Here we focus on the role of correlation among avalanches as the main source of the noise peaks observed. The present theory is based on first principles statistics of elementary events clustered in time-amplitude correlated avalanches. A noise spectral power master equation suitable to explain any peaked noise spectra is analytically achieved. Excellent agreement with our noise experiments in superconductors and with recent experiments in Escherichia coli, in single DNA molecule, and in single electron tunneling is reporte