Photocatalytic activities of mesoporous RuO2/TiO2 heterojunction nanocomposites for organic dye decomposition and H2 production by methanol photoreforming have been studied as a function of the RuO2 loading in the 1 10 wt % range. An optimum RuO2 loading was evidenced for both kinds of reaction, the corresponding nanocomposites showing much higher activities than pure TiO2 and commercial reference P25. Thus, 1 wt % RuO2/TiO2 photocatalyst led to the highest rates for the degradation of cationic (methylene blue) and anionic (methyl orange) dyes under UV light illumination. To get a better understanding of the mechanisms involved, a comprehensive investigation on the photogenerated charge carriers, detected by electron spin resonance (ESR) spectroscopy in the form of O, Ti3+, and O2 trapping centers, was performed. Along with the key role of superoxide paramagnetic species in the photodecomposition of organic dyes, ESR measurements revealed a higher amount of trapped holes in the case of the 1 wt % RuO2/TiO2 photocatalyst that allowed rationalizing the trends observed. On the other hand, a maximum average hydrogen production rate of 618 μmol h1 was reached with 5 wt % RuO2/TiO2 photocatalyst to be compared with 29 μmol h1 found without RuO2. Favorable band bending at the RuO2/TiO2 interface and the key role of photogenerated holes have been proposed to explain the highest activity of the RuO2/TiO2 photocatalysts for hydrogen production. These findings open new avenues for further design of RuO2/TiO2 nanostructures with a fine tuning of the RuO2 nanoparticle distribution in order to reach optimized vectorial charge distribution and enhanced photocatalytic hydrogen production rates.

Uddin, M., Babot, O., Thomas, L., Olivier, C., Redaelli, M., D'Arienzo, M., et al. (2015). New insights into the photocatalytic properties of RuO2/TiO2 mesoporous heterostructures for hydrogen production and organic pollutant photodecomposition. JOURNAL OF PHYSICAL CHEMISTRY. C, 119(13), 7006-7015 [10.1021/jp512769u].

New insights into the photocatalytic properties of RuO2/TiO2 mesoporous heterostructures for hydrogen production and organic pollutant photodecomposition

REDAELLI, MATTEO;D'ARIENZO, MASSIMILIANO;MORAZZONI, FRANCA;
2015

Abstract

Photocatalytic activities of mesoporous RuO2/TiO2 heterojunction nanocomposites for organic dye decomposition and H2 production by methanol photoreforming have been studied as a function of the RuO2 loading in the 1 10 wt % range. An optimum RuO2 loading was evidenced for both kinds of reaction, the corresponding nanocomposites showing much higher activities than pure TiO2 and commercial reference P25. Thus, 1 wt % RuO2/TiO2 photocatalyst led to the highest rates for the degradation of cationic (methylene blue) and anionic (methyl orange) dyes under UV light illumination. To get a better understanding of the mechanisms involved, a comprehensive investigation on the photogenerated charge carriers, detected by electron spin resonance (ESR) spectroscopy in the form of O, Ti3+, and O2 trapping centers, was performed. Along with the key role of superoxide paramagnetic species in the photodecomposition of organic dyes, ESR measurements revealed a higher amount of trapped holes in the case of the 1 wt % RuO2/TiO2 photocatalyst that allowed rationalizing the trends observed. On the other hand, a maximum average hydrogen production rate of 618 μmol h1 was reached with 5 wt % RuO2/TiO2 photocatalyst to be compared with 29 μmol h1 found without RuO2. Favorable band bending at the RuO2/TiO2 interface and the key role of photogenerated holes have been proposed to explain the highest activity of the RuO2/TiO2 photocatalysts for hydrogen production. These findings open new avenues for further design of RuO2/TiO2 nanostructures with a fine tuning of the RuO2 nanoparticle distribution in order to reach optimized vectorial charge distribution and enhanced photocatalytic hydrogen production rates.
Articolo in rivista - Articolo scientifico
Physical and Theoretical Chemistry; Electronic, Optical and Magnetic Materials; Surfaces, Coatings and Films; Energy (all)
English
2015
119
13
7006
7015
open
Uddin, M., Babot, O., Thomas, L., Olivier, C., Redaelli, M., D'Arienzo, M., et al. (2015). New insights into the photocatalytic properties of RuO2/TiO2 mesoporous heterostructures for hydrogen production and organic pollutant photodecomposition. JOURNAL OF PHYSICAL CHEMISTRY. C, 119(13), 7006-7015 [10.1021/jp512769u].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/88812
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