Cinthia Alegre | Consiglio Nazionale delle Ricerche (CNR) (original) (raw)

Address: Messina, Sicilia, Italy

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Papers by Cinthia Alegre

RSC Adv., 2015

ABSTRACT Pd-based catalysts supported on commercial carbon supports (Ketjenblack and Vulcan) have... more ABSTRACT Pd-based catalysts supported on commercial carbon supports (Ketjenblack and Vulcan) have been studied for both the ORR and the OER. Pd proved to be a suitable bi-functional catalyst for the ORR and the OER, with Vulcan as the carbon support providing the highest stability during accelerated degradation tests.

International Journal of Hydrogen Energy, 2014

ABSTRACT The use of liquid organic hydrides as hydrogen carriers is a promising storage and deliv... more ABSTRACT The use of liquid organic hydrides as hydrogen carriers is a promising storage and delivery system due to the advantages of using liquid-based infrastructures and its economic feasibility compared to other conventional systems. The reversible dehydrogenation/hydrogenation of liquid organic hydrides is a key point for the development of highly performance reactors. In this study different carbon materials have been investigated as platinum supports, including carbon nanofibers, carbon black, carbon xerogel, activated carbon and ordered mesoporous carbon. To individuate the effect of the carbon support on the catalytic activity, platinum particles were synthesized by a microemulsion procedure. The analysis of the hydrogen evolution curves indicate that the support BET surface area plays a very important role on the initial catalytic activity, obtaining a maximum rate of 220 mmol g(pt)(-1) min(-1) when using an ordered mesoporous carbon with a surface area of 930 m(2) g(-1). Nevertheless, the analysis of catalytic activity at prolonged duration indicates a better behavior toward deactivation for supports characterized by wide pores and low graphitization degree like carbon black or carbon xerogel, despite their lower initial dehydrogenation rate (100-140 mmol g(pt)(-1) min(-1)). The ultimate use in the dehydrogenation reactor as well as the operation conditions will define the best catalyst structure from the point of view of the carbon support. Copyright

Chemcatchem, 2013

ABSTRACT A high surface area, highly mesoporous carbon xerogel was synthesised and used as a supp... more ABSTRACT A high surface area, highly mesoporous carbon xerogel was synthesised and used as a support in the preparation of platinum–ruthenium catalysts by different synthetic routes. The platinum–ruthenium carbon xerogel catalysts were physico-chemically characterised and used for the chemical electro-oxidation of methanol. The synthetic routes pursued included: 1) impregnation with metal chloride precursors and reduction with two different reducing agents: sodium borohydride and formic acid; 2) a microemulsion-based method and 3) a sulfite complex method, which led to catalysts with different physico-chemical features that strongly influence their catalytic behaviour towards methanol oxidation. The electro-oxidation of methanol was found to depend on both the crystal size and the extent of active phase reduction as well as on the platinum concentration on the catalyst surface, which were maximised for the impregnation method and reduction with formic acid.

The Journal of Physical Chemistry C, 2013

ABSTRACT PtRu catalysts were prepared using a highly mesoporous carbon xerogel submitted to diffe... more ABSTRACT PtRu catalysts were prepared using a highly mesoporous carbon xerogel submitted to different oxygen functionalization treatments: diluted and concentrated nitric acid as well as gas-phase 5% O2–N2 oxidation. Catalysts with 20 wt % loading and equimolar Pt:Ru metallic phase were prepared using an impregnation procedure involving chemical reduction with formic acid. The so-obtained carbon materials, as well as the different catalysts synthesized, were characterized by means of N2 physisorption, temperature-programmed desorption (TPD), X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Cyclic voltammetry and chronoamperometry were performed to study their activity toward carbon monoxide and methanol oxidation. Functionalization of the carbon support was found to play a definitive role in the interaction between carbon material and the active phase, determining metallic dispersion, alloying degree, and reduction extent. The activity of the catalysts in methanol electro-oxidation was directly related to the metal oxidation state and alloying degree.