Nanostructured carbon films were grown by supersonic cluster beam deposition using a focusing nozzle for selecting small clusters and increasing the deposition rate. The films present a pore structure in the mesopore range (maximum of the pore size distribution at 34 Å) with a specific surface area of 665 m2/g. Temperature programmed desorption (TPD) analysis shows sorption of hydrogen after hydrogen exposure. In the near edge X-ray absorption fine structure (NEXAFS) spectra a strong peak at ~ 288.5 eV, related to C-H bonds (hydrogen chemisorbed), is evident. After sample annealing at temperature of approximately 500°C, the prominent C-H* peak is strongly reduced. The samples experienced reiterated exposures to water vapor and hydrogen and subsequent annealings. The partial restoration of the C-H* peak after exposures and its decrease after moderate heating indicate that the sorption and release of hydrogen is a reversible process.

NEXAFS characterization of nanostructured carbon thin-films exposed to hydrogen / C. Lenardi, E. Barborini, V. Briois, L. Lucarelli, P. Piseri, P. Milani. - In: DIAMOND AND RELATED MATERIALS. - ISSN 0925-9635. - 10:3-7(2001), pp. 1195-1200. ((Intervento presentato al 11. convegno European Conference on Diamond, Diamond-like Materials, Carbon Nanotubes, Nitrides and Silicon Carbide (Diamond 2000) tenutosi a OPORTO, PORTUGAL nel 2000.

NEXAFS characterization of nanostructured carbon thin-films exposed to hydrogen

C. Lenardi
Primo
;
P. Piseri
Penultimo
;
P. Milani
Ultimo
2001

Abstract

Nanostructured carbon films were grown by supersonic cluster beam deposition using a focusing nozzle for selecting small clusters and increasing the deposition rate. The films present a pore structure in the mesopore range (maximum of the pore size distribution at 34 Å) with a specific surface area of 665 m2/g. Temperature programmed desorption (TPD) analysis shows sorption of hydrogen after hydrogen exposure. In the near edge X-ray absorption fine structure (NEXAFS) spectra a strong peak at ~ 288.5 eV, related to C-H bonds (hydrogen chemisorbed), is evident. After sample annealing at temperature of approximately 500°C, the prominent C-H* peak is strongly reduced. The samples experienced reiterated exposures to water vapor and hydrogen and subsequent annealings. The partial restoration of the C-H* peak after exposures and its decrease after moderate heating indicate that the sorption and release of hydrogen is a reversible process.
Settore FIS/03 - Fisica della Materia
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/183785
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