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See detailStudy of photocatalytic decomposition of hydrogen peroxide over ramsdellite-MnO2 by O2-pressure monitoring
Páez Martínez, Carlos ULg; Liquet, Dimitri ULg; Calberg, Cédric ULg et al

in Catalysis Communications (2011), 15

The catalytic and photocatalytic activities of ramsdellite type manganese oxide, R-MnO2 were studied from the initial rate of decomposition of H2O2 in aqueous solution. The kinetic study was followed by ... [more ▼]

The catalytic and photocatalytic activities of ramsdellite type manganese oxide, R-MnO2 were studied from the initial rate of decomposition of H2O2 in aqueous solution. The kinetic study was followed by the production of O2 via gas pressure monitoring (O2-monitored method), in the dark and under visible light irradiation (λ≥400 nm), at 20 °C. Experimental data showed that the rate of H2O2 decomposition, under visible light irradiation and in the dark, obeys the first order kinetic law.While in the dark the H2O2 decomposition rate bymass unit was around 6.88 mmol g−1 s−1, under visible light irradiation theH2O2 decomposition rate achieved a maximal value of 15.13 mmol g−1 s−1. The increase in the H2O2 decomposition, by effect of the visible light, was observed in ranges of catalyst concentrations from 16 to 374 mg L−1. These results reflect the potential of R-MnO2 as a photoactive catalyst, being a consequence of presumed photoreduction of Mn4+centers. [less ▲]

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See detailImprovement in the methylene blue adsorption capacity and photocatalytic activity of H2-reduced rutile-TiO2 caused by Ni(II)porphyrin preadsorption
Páez Martínez, Carlos ULg; Lambert, Stéphanie ULg; Poelman, Dirk et al

in Applied Catalysis B : Environmental (2011), 106

H2-reduced rutile-TiO2 xerogel (Ti-700), obtained via the sol–gel process, was found to strongly adsorb the Ni(II)-5,10,15,20-tetrakis(4-carboxyphenyl)-porphyrin (NiTCPP) from a methanolic solution ... [more ▼]

H2-reduced rutile-TiO2 xerogel (Ti-700), obtained via the sol–gel process, was found to strongly adsorb the Ni(II)-5,10,15,20-tetrakis(4-carboxyphenyl)-porphyrin (NiTCPP) from a methanolic solution, despite its very low specific surface area (SBET ≈ 2 m2 g−1). UV/vis spectroscopy analysis showed that after calcination at 700 ◦C and reduction under H2 flow at 400 ◦C, the TiO2-xerogel increased its NiTCPP-adsorption capacity by surface area unit by up to 120 times. The effect of the porphyrin presence in the catalytic performances of TiO2-xerogels was studied through three kinetics models: (i) the pseudo-first-order kinetic model; (ii) the pseudo-second-order kinetic model, which are used to describe the adsorption rate based on the adsorption capacity of the catalysts; and (iii) the Langmuir–Hinshelwood kinetic model which is used to describe the photocatalytic degradation rate of methylene blue (MB). A significant improvement in the efficiency of Ti-700 was observed after the porphyrin-adsorption process (NiTCPP/Ti-700): MB-adsorption capacity at equilibrium and the apparent MB-photoconversion constant, kapp, of NiTCPP/Ti-700 were both up to 2 times higher than those observed for the Ti-700. [less ▲]

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See detailActivated-carbon-xerogel/TiO2-P25 composite photocatalysts with high activity for the degradation of p-nitrophenol
Páez Martínez, Carlos ULg; Contreras, María; Olivera-Fuentes, Claudio et al

Poster (2010, July)

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See detailAg-and SiO2-doped porous TiO2 with enhanced thermal stability
Braconnier, Benoît ULg; Páez Martínez, Carlos ULg; Lambert, Stéphanie ULg et al

in Microporous and Mesoporous Materials (2009), 122

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See detailDécomposition photocatalytique de polluants et de micro-organismes dans l'eau
Heinrichs, Benoît ULg; Pirard, Jean-Paul ULg; Lambert, Stéphanie ULg et al

E-print/Working paper (2008)

Dans le cadre de la réutilisation des eaux usées et de l’accès limité à l’eau potable dans certaines régions du globe, de nouvelles techniques de désinfection nécessitant de faibles consommations ... [more ▼]

Dans le cadre de la réutilisation des eaux usées et de l’accès limité à l’eau potable dans certaines régions du globe, de nouvelles techniques de désinfection nécessitant de faibles consommations d’énergie sont étudiées. Cette eau n’est pas toujours potable et contient des polluants qui induisent des mutations génétiques pouvant conduire au développement de cancers ou encore des micro-organismes pathogènes causant des maladies graves. Depuis la découverte des propriétés de photodégradation oxydante du dioxyde de titane (TiO2), la photocatalyse hétérogène est utilisée pour l’élimination des polluants environnementaux et des micro-organismes. [less ▲]

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See detailPhotodegradation of bacteria with TiO2 produced by sol-gel method
Tasseroul, Ludivine ULg; Pàez Martinez, Carlos ULg; Braconnier, Benoît et al

Poster (2007)

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