title: Enhancing the Photocatalytic Activity of Sr4Al14O25: Eu2+, Dy3+Persistent Phosphors by Codoping with Bi3+Ions.
abstract: The photocatalytic activity of Bismuth-codoped Sr4Al14O25: Eu2+, Dy3+persistent phosphors is studied by monitoring the degradation of the blue methylene dye UV light irradiation. Powder phosphors are obtained by a combustion synthesis method and a postannealing process in reductive atmosphere. The XRD patterns show a single orthorhombic phase Sr4Al14O25: Eu2+, Dy3+, Bi3+phosphors even at high Bismuth dopant concentrations of 12 mol%, suggesting that Bi ions are well incorporated into the host lattice. SEM micrographs show irregular micrograins with sizes in the range of 0.5-20 μm. The samples present an intense greenish-blue fluorescence and persistent emissions at 495 nm, attributed to the 5d-4f allowed transitions of Eu2+. The fluorescence decreases as Bi concentration increases; that suggest bismuth-induced traps formation that in turn quench the luminescence. The photocatalytic evaluation of the powders was studied under both 365 nm UV and solar irradiations. Sample with 12 mol% of Bi presented the best MB degradation activity; 310 min of solar irradiation allow 100% MB degradation, whereas only 62.49% MB degradation is achieved under UV irradiation. Our results suggest that codoping the persistent phosphors with Bi3+can be an alternative to enhance their photocatalytic activity.
authors.affiliation: Facultad de Ciencias Físico-Matemáticas, Universidad Autónoma de Coahuila, Saltillo, Mexico.
authors.forename: Carlos R
authors.initials: CR
authors.lastname: García
authors.affiliation: Grupo de Espectroscopia de Materiales Avanzados y Nanoestructurados (GEMANA), Centro de Investigaciones en Óptica, León, Mexico.
authors.forename: Jorge
authors.initials: J
authors.lastname: Oliva
authors.affiliation: Facultad de Ciencias Físico-Matemáticas, Universidad Autónoma de Coahuila, Saltillo, Mexico.
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Romero
authors.affiliation: Grupo de Espectroscopia de Materiales Avanzados y Nanoestructurados (GEMANA), Centro de Investigaciones en Óptica, León, Mexico.
authors.forename: Luis A
authors.initials: LA
authors.lastname: Diaz-Torres