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Photoisomerization of norbornadiene to quadricyclane using transition metal doped TiO2 / Lun Pan in Industrial & engineering chemistry research, Vol. 49 N° 18 (Septembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8526–8531 Titre : Photoisomerization of norbornadiene to quadricyclane using transition metal doped TiO2 Type de document : texte imprimé Auteurs : Lun Pan, Auteur ; Ji-Jun Zou, Auteur ; Xiangwen Zhang, Auteur Année de publication : 2010 Article en page(s) : pp. 8526–8531 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Photoisomerization  Norbornadiene Résumé : Metal(V, Fe, Ce, Cu, Cr)-doped TiO2 were synthesized for the photoisomerization of norbornadiene. Characterizations indicate that V and Fe are located in the substitutional sites of TiO2, Ce ions dispersed in the interstitial sites, while Cr and Cu aggregated on the surface. The order of activity is Fe−TiO2 > V−TiO2 > Cr−TiO2 > Ce−TiO2 > TiO2 > Cu−TiO2, suggesting the local structure and type of dopant are crucial. Materials with various V and Fe content were further studied. Fe ions are well dispersed in TiO2 lattice even at high metal content, whereas many separated V2O5 phases are formed. The activity of V−TiO2 changes with V content and the optimal Ti/V ratio is 15, but the activity of Fe−TiO2 is independent of the metal content. Attributed to the high dispersion, Fe−TiO2 is much more active than V−TiO2. The photoreactivity is correlated with the surface lattice oxygen, and a mechanism is proposed to explain the photoisomerization and role of Fe dopant. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100841w [article] Photoisomerization of norbornadiene to quadricyclane using transition metal doped TiO2 [texte imprimé] / Lun Pan, Auteur ; Ji-Jun Zou, Auteur ; Xiangwen Zhang, Auteur . - 2010 . - pp. 8526–8531. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8526–8531 Mots-clés : Photoisomerization  Norbornadiene Résumé : Metal(V, Fe, Ce, Cu, Cr)-doped TiO2 were synthesized for the photoisomerization of norbornadiene. Characterizations indicate that V and Fe are located in the substitutional sites of TiO2, Ce ions dispersed in the interstitial sites, while Cr and Cu aggregated on the surface. The order of activity is Fe−TiO2 > V−TiO2 > Cr−TiO2 > Ce−TiO2 > TiO2 > Cu−TiO2, suggesting the local structure and type of dopant are crucial. Materials with various V and Fe content were further studied. Fe ions are well dispersed in TiO2 lattice even at high metal content, whereas many separated V2O5 phases are formed. The activity of V−TiO2 changes with V content and the optimal Ti/V ratio is 15, but the activity of Fe−TiO2 is independent of the metal content. Attributed to the high dispersion, Fe−TiO2 is much more active than V−TiO2. The photoreactivity is correlated with the surface lattice oxygen, and a mechanism is proposed to explain the photoisomerization and role of Fe dopant. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100841w

Visible–light–induced photodegradation of rhodamine B over hierarchical TiO2 / Lun Pan in Industrial & engineering chemistry research, Vol. 51 N° 39 (Octobre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12782-12786 Titre : Visible–light–induced photodegradation of rhodamine B over hierarchical TiO2 : Effects of storage period and water-mediated adsorption switch Type de document : texte imprimé Auteurs : Lun Pan, Auteur ; Ji-Jun Zou, Auteur ; Xin-Yu Liu, Auteur Année de publication : 2012 Article en page(s) : pp. 12782-12786 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Adsorption  Storage  Titanium  oxide  Photochemical  degradation  Visible  radiation Résumé : Hierarchical TiO2 was prepared via hydrolysis method and characterized by XRD, N2 adsorption―desorption, UV―vis diffusion, and NH3―TPD. With the increase of calcination temperature, the surface area and surface hydroxyls of UV―vis diffusion, and NH3―TPD. With the increase of calcination temperature, the surface area and surface hydroxyls of prepared materials decrease rapidly. The photoactivity was evaluated using the self-sensitized photodegradation of rhodamine B under visible light The fresh samples show higher activity than P-25 due to higher surface area and more effective light utilization. After stored in air for ca. half a year, the materials show significantly increased photoactivity, due to the prebonding of water on surface bridging hydroxyls, which induces water-mediated adsorption switch from covalent mode to electrostatic one. Water treatment further promotes the photoactivity of stored samples, because more water are bonded on TiO2 surface. It is found that the water-mediated effect closely depends on the surface area and amount of surface bridging hydroxyls. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419233 [article] Visible–light–induced photodegradation of rhodamine B over hierarchical TiO2 : Effects of storage period and water-mediated adsorption switch [texte imprimé] / Lun Pan, Auteur ; Ji-Jun Zou, Auteur ; Xin-Yu Liu, Auteur . - 2012 . - pp. 12782-12786. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12782-12786 Mots-clés : Adsorption  Storage  Titanium  oxide  Photochemical  degradation  Visible  radiation Résumé : Hierarchical TiO2 was prepared via hydrolysis method and characterized by XRD, N2 adsorption―desorption, UV―vis diffusion, and NH3―TPD. With the increase of calcination temperature, the surface area and surface hydroxyls of UV―vis diffusion, and NH3―TPD. With the increase of calcination temperature, the surface area and surface hydroxyls of prepared materials decrease rapidly. The photoactivity was evaluated using the self-sensitized photodegradation of rhodamine B under visible light The fresh samples show higher activity than P-25 due to higher surface area and more effective light utilization. After stored in air for ca. half a year, the materials show significantly increased photoactivity, due to the prebonding of water on surface bridging hydroxyls, which induces water-mediated adsorption switch from covalent mode to electrostatic one. Water treatment further promotes the photoactivity of stored samples, because more water are bonded on TiO2 surface. It is found that the water-mediated effect closely depends on the surface area and amount of surface bridging hydroxyls. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419233