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See detailPhysico-chemical properties and photocatalytic activity of P/Ag-doped TiO2 xerogels
Bodson Céline; Pirard, Sophie ULg; Pirard René et al

Conference (2013, July)

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See detailPhysico-chemical properties and photocatalytic activity of calcined P-doped and P/Ag-doped TiO2 xerogels
Bodson, Céline; Pirard, Sophie ULg; Pirard, René ULg et al

Conference (2013, March 05)

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See detailHighly efficient organic/inorganic titania xerogels for photocatalysis applications
Bodson, Céline ULg; Bied, Catherine; Páez Martínez, Carlos ULg et al

Poster (2011)

TiO2 heterogeneous photocatalysis is an attractive technique for the complete destruction of undesirable contaminants either in aqueous or gaseous phase by using solar or artificial light illumination ... [more ▼]

TiO2 heterogeneous photocatalysis is an attractive technique for the complete destruction of undesirable contaminants either in aqueous or gaseous phase by using solar or artificial light illumination. The main drawback of TiO2 is that it can be activated only by UV light because of its large band gap (3.20 eV for anatase). Thus, it would be interesting to sensitize TiO2 to the whole visible region by doping with non-metal atoms such as phosphorus. Furthermore, it was found that the P-doped species could significantly increase the specific surface area of the materials, which consequently exhibit a higher content of surface hydroxyl groups. Upon band gap excitation of TiO2, the photoinduced electrons and positively charged holes can reduce and oxidize the species adsorbed on the TiO2 particles. The high degree of recombination between photogenerated electrons and holes is a major rate-limiting factor controlling the photocatalytic efficiency. Attempts to increase the titania efficiency have been made by doping P-doped TiO2 with metals, such as Ag. In the present study, a sol-gel method is developed to synthesize P-doped TiO2 and P/Ag-codoped xerogels by a cogelation method [1] based on the hydrolysis and the condensation of Ti(OC3H7)4 in the presence of a phosphoryled compound able to complex silver: NH2-(CH2)2-NH-(CH2)2-P(O)-(OC2H5)2, EDAP), in various alcohols. These xerogels are dried at 150°C under vacuum for 24 h, and calcined under air for 5 h at 350°C, 450°C, 550°C and 650°C. The resulting materials were characterized by ICP-AES, TG-DSC, TEM, XRD, nitrogen adsorption-desorption isotherms, FT-IR and diffuse reflectance measurements in the UV/Vis region. To measure the photoactivity of these new hybrid organic/inorganic titania xerogels, all these samples were tested for the degradation of p-nitrophenol under visible light. The titanium, phosphorus and silver contents in xerogels were confirmed by ICP-AES. As expected, theoretical and actual Ti/P molar ratio and Ag contents in xerogels are similar and then after washing with THF for 48 h. These results allow to conclude that EDAP and Ag are well incorporated within the TiO2 matrix: EDAP is anchored in the titania matrix by complexation and cogelation with TTIP [2], whereas silver, first incorporated by complexation through the ethylenediamine fragment of EDAP, is present in the xerogels in the form of nanoparticles. It was found that the phosphor-doped species could significantly increase the surface area of the materials. [2] It is noteworthy that the porosity of these materials is not affected by the addition of silver acetate during the synthesis, a very slight decrease of the specific surface area being observed in all cases. The organic/inorganic hybrid titania materials display very high photocatalytic efficiencies in the degradation of p-nitrophenol compared to pure titania. Deeper investigations concerning the structure of these materials should enable a better understanding of the photocatalytic mechanisms involved with these hybrids and will soon be reported. 1. S. Lambert, K. Y. Tran, G. Arrachart, F. Noville, C. Henrist, C. Bied, J. J. E. Moreau, M. Wong Chi Man, B. Heinrichs, Micropor. Mesopor. Mater. 2008, 115, 609. 2. C.J.Bodson1, S.D. Lambert1, C. Alié1, X. Cattoën2, J-P. Pirard1, C. Bied2, M.Wong Chi Man2, B. Heinrichs1 ,Micropor. Mesopor. Mater. 2010, 134,157 [less ▲]

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See detailRelationships between the structure of P-doped TiO2 xerogels and their photocatalytic properties
Bodson, Céline ULg; Cattoën, Xavier; Bied, Catherine et al

Conference (2011)

TiO2 heterogeneous photocatalysis has been the subject of numerous recent investigations as it is an attractive technique for the complete destruction of undesirable contaminants both in aqueous and ... [more ▼]

TiO2 heterogeneous photocatalysis has been the subject of numerous recent investigations as it is an attractive technique for the complete destruction of undesirable contaminants both in aqueous and gaseous phase by using solar or artificial light illumination. However, TiO2-based materials present a large band gap and therefore only a small fraction of solar light, in the UV region, can be utilized. Furthermore, anatase-TiO2 transforms to the rutile structure at temperatures relatively lower, which greatly reduces surface areas of the particles resulting in the decrease in photocatalytic ability of TiO2. To counter both disadvantages, several studies have been conducted by doping non-metallic elements, such as phosphor, into the Ti-O framework to form TiO2 solutions. In the present study, a sol-gel method is developed to synthesize P-doped TiO2 xerogels by a cogelation method based on the hydrolysis and the condensation of Ti(OC3H7)4 with functionalized P alkoxides: NH2-(CH2)2-NH-(CH2)2-P(O)-(OC2H5)2, or (C2H5O)2-P(O)-(CH2)7-CH3, in various alcohols. These xerogels are dried at 150°C under vacuum for 24 h, and calcined under air for 6 h at 350°C, 450°C, 550°C and 650°C. The resulting materials were characterized by TG-ATD, TEM, XRD, nitrogen adsorption-desorption isotherms, FT-IR and diffuse reflectance measurements in the UV/Vis region. It was found that the phosphor-doped species could significantly increase the surface area of the materials. Moreover, the phosphor-doping improved the thermal stability of titania and decreased the phase transformation of anatase to rutile. Diffuse reflectance measurements proved that the modification by phosphor shifted the absorption edge of titania to the visible region, making it an effective photocatalyst in visible light. This is shown by the degradation of p-nitrophenol under visible light irradiation. The excellent photocatalytic activity of P-doped TiO2 xerogels compared to pure TiO2 could be explained by its high surface area and small crystallite size. [less ▲]

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See detailRelations entre la structure et la texture poreuse de xérogels de TiO2 dopés au phosphore et leurs propriétés photocatalytiques
Bodson, Céline ULg; Cattoën, Xavier; Bied, Catherine et al

in Récents Progrès en Génie des Procédés, Lavoisier Technique et Documentation, Volume 101, 6 p. (CD-ROM) (2011)

The sol-gel process is used to prepare phosphorus (P)-doped TiO2 xerogels by cogelation of Ti(O-iPr)4 with a functionalized P-based alkoxide : NH2-(CH2)2-NH-(CH2)2-P(O)-(OEt)2, in various alcohols. These ... [more ▼]

The sol-gel process is used to prepare phosphorus (P)-doped TiO2 xerogels by cogelation of Ti(O-iPr)4 with a functionalized P-based alkoxide : NH2-(CH2)2-NH-(CH2)2-P(O)-(OEt)2, in various alcohols. These xerogels were dried under vacuum at 150°C during 12 h, and calcined under air for 5 h at 350 °C, 450 °C, 550 °C and 650 °C. The samples obtained were characterized by X-ray diffraction, nitrogen adsorption-desorption isotherms and diffuse reflectance spectroscopy in UV/Vis region. The presence of phosphorus in the samples leads to a significant increase of their specific surface area, proportionally to the amount of phosphorus in the sample. Furthermore, the doping of the TiO2 by a phosphonate compound increases the thermal stability of the TiO2 and delays the phase transformation from amorphous to anatase. The diffuse reflectance measurements clearly show the translation of absorption peak of TiO2 towards the visible region when the content in phosphorus increases. Indeed, it is observed a degradation of the p-nitrophenol under visible light by using these P-doped TiO2 xerogels, which means that the P-doping enhances the photocatalytic activity in the visible region. [less ▲]

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See detailEffects of additives and solvents on the gel formation rate and on the texture of P- and Si-doped TiO2 materials
Bodson, Céline ULg; Lambert, Stéphanie ULg; Alié, Christelle ULg et al

in Microporous and Mesoporous Materials (2010), 134

Organic/inorganic hybrid TiO2 xerogels have been synthesized from titanium tetraisopropoxide and an organosilylated or organophosphorylated additive either in 2-methoxyethanol or isopropanol. The ... [more ▼]

Organic/inorganic hybrid TiO2 xerogels have been synthesized from titanium tetraisopropoxide and an organosilylated or organophosphorylated additive either in 2-methoxyethanol or isopropanol. The mechanisms of formation of the gels have been studied before gelation by liquid NMR spectroscopy and connected to their structure after drying analyzed by Raman spectroscopy, solid state NMR and N2 adsorption/desorption. The effects of the additives and solvents on the gel formation rate and on the texture of the xerogel have been addressed. [less ▲]

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See detailAn in-situ NMR analysis of the formation of P- and SiO2-doped TiO2 xerogels
Bodson, Céline ULg; Lambert, Stéphanie ULg; Cattoën, Xavier et al

Poster (2010, July)

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See detailAn in situ NMR analysis of the formation of P- and SiO2-doped TiO2 xerogels
Bodson, Céline ULg; Lambert, Stéphanie ULg; Cattoën, Xavier et al

Poster (2009)

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See detailSynthesis of Ag/TiO2 hybrid photocatalysts by sol-gel process with new P-alkoxide functionalized ligands
Lambert, Stéphanie ULg; Bied, Catherine; Bodson, Céline et al

Poster (2009)

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See detailTailor-made morphologies for Pd/SiO2 catalysts through sol-gel process with various silylated ligands
Lambert, Stéphanie ULg; Tran, Kim Yên; Arrachart, Guilhem et al

in Microporous and Mesoporous Materials (2008), 115

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See detailSynthesis of highly dispersed Pd/SiO2 cogelled xerogel catalysts from various silylated ligands
Lambert, Stéphanie ULg; Tran, Kim Yên; Arrachart, Guilhem et al

Poster (2007)

Detailed reference viewed: 15 (3 ULg)