Navegando por Palavras-chave "Anatase-to-Rutile phase transformation"

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    Hexagonal-Nb2O5/Anatase-TiO2 mixtures and their applications in the removal of Methylene Blue dye under various conditions
    (Elsevier Science Sa, 2017) Ferraz, Nathalia Pereira [UNIFESP]; Marcos, Francielle Candian Firmino; Nogueira, André Esteves; Martins, Alysson Stefan; Lanza, Marcos Roberto de Vasconcelos; Assaf, Elisabete Moreira; Asencios, Yvan Jesus Olortiga [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    To the best of our knowledge, catalysts based on mixtures of Hexagonal-Nb2O5/Anatase-TiO2 have not been well studied yet. In this sense, the aim of the present study was to synthesize, characterize and explore the catalytic activity of Hexagonal-Nb2O5/Anatase-TiO2 catalysts in the removal of Methylene Blue dye, MB (used as model molecule of organic pollutant in aqueous solution), under UV-light (253.7 nm), Visible-light (400–700 nm) and Visible-light (400–700 nm) plus H2O2. The influence of the Hexagonal-Nb2O5 on the activity of a commercial TiO2 (Rutile/Anatase) was evaluated. The catalysts were characterized by various techniques; XRD, H2-TPR, BET, EDX, DRS and SEM. Our results show that the presence of Hexagonal-Nb2O5 hinders the Anatase-to-Rutile phase transformation of TiO2, sensitizes and enhances the photocatalytic activity of the commercial TiO2 under white-light. The best catalyst was the sample with 60 wt % of Nb2O5 (0.6NbTi sample), showing the highest removal values of MB in aqueous solutions under white-light and white-light plus H2O2. Additionally, the present paper shows a new route to obtain a single hexagonal phase of Nb2O5 using Niobium Ammoniacal Oxalate by a simple and economic route.