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Title: Photocatalytic hydrogen production with visible light over Pt-interlinked hybrid composites of cubic-phase and hexagonal-phase CdS
Other Titles: Journal of Physical Chemistry C
Authors: Silva, Luciana A.
Su, Young Ryu
Choi, Jina
Choi, Wonyong
Hoffmann, Michael R.
Issue Date: 2008
Abstract: A hybrid photocatalytic system, which is based on a mixed-phase cadmium sulfide matrix composed of nanoparticulate cubic-phase CdS (c-CdS) with average particle diameters of 13 nm and a bandgap energy of 2.6 eV, is coupled with bulk-phase hexagonal CdS (hex-CdS) that has a bandgap energy of 2.3 eV and is interlinked with elemental platinum deposits. The resulting hybrid nanocomposite catalysts are photocatalytically efficient with respect to hydrogen gas production from water with visible light irradiation at λ > 420 nm. Rates of H2 production approaching 1.0 mmol-H2 g−1 h−1 are obtained with a c-CdS/Pt/hex-CdS composite photocatalyst, in the presence of a mixed sodium sulfide and sodium sulfite background electrolyte system at pH 14. In contrast, the same composite produces H2 a rate of 0.15 mmol g−1 h−1 at pH 7 in a water-isopropanol solvent system. The relative order of reactivity for the synthesized hybrid catalysts was found to be c-CdS/Pt/hex-CdS > Pt/c-CdS/hex-CdS > Pt/hex-CdS > hex-CdS > c-CdS/hex-CdS > quantum-sized c-CdS. A mechanism involving enhanced lifetimes of electron−hole trapping states that are dependent on the surface chemistry of hydrated CdS involving surface hydroxyl (>CdOH) and sulfhydryl groups (>CdSH) are invoked.
Description: Texto completo: acesso restrito. p. 12069-12073
URI: http://repositorio.ufba.br/ri/handle/ri/13987
ISSN: 1932-7447
Appears in Collections:Artigos Publicados em Periódicos (Quimica)

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