Photocatalytic storing of O2 as H2O2 mediated by high surface area CuO. Evidence for a reductive-oxidative interfacial mechanism.
Langmuir
; 21(18): 8554-9, 2005 Aug 30.
Article
en En
| MEDLINE
| ID: mdl-16114971
CuO powders with a high specific surface area are shown to be able to produce H(2)O(2) in aqueous solution under simulated light irradiation. The highest rate of peroxide production was observed under mild experimental conditions using O(2) and a large surface area photocatalyst CuO irradiated with a solar simulator having light intensities between 60 and 90 mW/cm(2). The CuO employed had a specific surface area (SSA) of 64.8-70.1 m(2)/g and was prepared in a tubular furnace by controlled thermal decomposition of precipitated copper oxalate. The CuO particles produced were 1 mum cubes with primary particles around 15 nm. No peroxide was produced under the same conditions with commercial CuO, with SSA 200 times lower. The CuO synthesized during this work was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), specific surface area [Brunauer-Emmett-Teller (BET)], porosity, and X-ray photoelectron spectroscopy (XPS). From XPS, it was observed that only Cu(II) was present in the unused and used CuO. This indicates that the redox transient species involving other Cu oxidation states disappear very fast during the reaction, regenerating Cu(II) during H(2)O(2) production. Diverse experiments provided some evidence for the possible interfacial reaction mechanism leading to H(2)O(2), following the initial step of O(2)(-)(.) formation on the CuO surface under irradiation with photons, with energies exceeding the band gap of CuO. A photocatalyzed degradation of a concentrated 4-chlorophenol (4-CP) solution was observed under solar-simulated light in the presence of CuO.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Oxígeno
/
Cobre
/
Peróxido de Hidrógeno
Idioma:
En
Revista:
Langmuir
Asunto de la revista:
QUIMICA
Año:
2005
Tipo del documento:
Article
País de afiliación:
Suiza
Pais de publicación:
Estados Unidos