Improved photocatalytic activity of d-FeOOH by using H2O2 as an electron acceptor.
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2017
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Resumo
In this work, d-FeOOH nanoparticles were synthesized by a simple co-precipitation method and used as a
photocatalyst in the presence of H2O2 for the oxidation of Rhodamine B (RhB) dye under artificial light.
The d-FeOOH was characterized by powder X-ray diffraction, 57Fe Mössbauer spectroscopy, N2
adsorption/desorption and UV–vis diffuse reflectance measurements. The d-FeOOH nanoparticles have
high specific surface area (101 m2 g 1) and optical bandgap energy of 2.02 eV. Under artificial light, only
59% of RhB (100 mL; 20 mg L 1) was photocatalytically degraded by d-FeOOH in 60 min reaction.
However, after adding H2O2, the photocatalytic activity of d-FeOOH was significantly improved, reaching
87% of dye removal. Tests using scavengers of reactive species and EPR analysis revealed that h+ and OH
are the main species in this system. Based on the experimental results, the mechanism of RhB
photodegradation in the presence of d-FeOOH and H2O2 was proposed. By this mechanism, the OH can
be formed by direct water oxidation or by H2O2 reduction, as the electron transfer from the conduction
band of d-FeOOH to H2O2 is thermodynamically favorable. Moreover, the H2O2 retards the electron-hole
recombination in d-FeOOH, thus increasing its photocatalytic activity. Given its high efficiency for
degrading RhB in water, d-FeOOH revealed to be a promising photocatalyst to be tested in the oxidation of
emerging pollutants for the environmental decontamination.
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Iron oxides, Dye oxidation, Photodegradation, Photocatalysts
Citação
SILVA, A. C. da et al. Improved photocatalytic activity of d-FeOOH by using H2O2 as an electron acceptor. Journal of Photochemistry and Photobiology A-Chemistry, v. 332, p. 54-59, jan. 2017. Disponível em: <http://www.sciencedirect.com/science/article/pii/S1010603016302416> Acesso em: 15 set. 2017.