RESEARCH PAPER Structure and photocatalytic properties of Nb-doped Bi 12 TiO 20 prepared by the oxidant peroxide method (OPM) Andre ´ E. Nogueira • Alan R. F. Lima • Elson Longo • Edson R. Leite • Emerson R. Camargo Received: 1 June 2014 / Accepted: 10 September 2014 Ó Springer Science+Business Media Dordrecht 2014 Abstract Pure (Bi 12 TiO 20 ) and niobium-doped (Bi 12 Ti 1-x Nb x O 20 , with ‘‘x’’ up to 0.15) bismuth titanates were prepared by the oxidant peroxide method (OPM) and used to photodegradate rhodamine b (RhB) under UV and visible radiation. Rietveld refinements showed samples consisting mainly of sillenite structure with small amounts of a perovskite secondary phase in the Nb-doped materials. These bismuth-based catalysts exhibited superior performance than the commercial TiO 2 , with band gaps ranging from 2.53 of pure Bi 12 TiO 20 to 2.73 eV depending on the amount of niobium added, which seems to be responsible for the improved photoactivity of the doped catalysts under UV radiation. Keywords Bismuth titanate Á Photocatalyst Á Peroxo-complexes Á Rhodamine b Introduction The photoactivation of semiconductors has received enormous attention in the last decade owing to their application for environmental cleanup, solar cells, water splitting, and others (Henderson 2011). In this process, the semiconductor is illuminated with UV or visible radiation to produce electron–hole pairs. Most of them recombine soon after, but a few of the remaining pairs produce OH • (hydroxyl) and O 2 •- (superoxide) radicals. These radicals are very power- ful oxidants and can react with organic compounds, converting them to water, carbon dioxide, and other simple substances (Herrmann 2010). The photocatalytic activity efficiency of semicon- ductors depends (i) on the charge separation of the electrons and holes and (ii) the recombination rate of the photogenerated electron–hole pairs. There are two basic strategies to improve the efficiency of photocat- alysts and to overcome their limitations. One is doping Electronic supplementary material The online version of this article (doi:10.1007/s11051-014-2653-2) contains supple- mentary material, which is available to authorized users. A. E. Nogueira Á A. R. F. Lima Á E. R. Leite Á E. R. Camargo (&) LIEC-Laborato ´rio Interdisciplinar de Eletroquı ´mica e Cera ˆmica, Departamento de Quı ´mica, UFSCar- Universidade Federal de Sa ˜o Carlos, Rod.Washington Luis km 235 CP 676, Sa ˜o Carlos, SP 13565-905, Brazil e-mail: camargo@ufscar.br A. E. Nogueira e-mail: andreesteves86@hotmail.com A. R. F. Lima e-mail: alan_rogerio2000@yahoo.com.br E. R. Leite e-mail: edson.leite@pq.cnpq.br E. Longo Instituto de Quı ´mica de Araraquara, UNESP- Universidade Estadual Paulista, Rua Francisco Degni, CP 355, Araraquara, SP 14801-907, Brazil e-mail: elson@iq.unesp.br 123 J Nanopart Res (2014) 16:2653 DOI 10.1007/s11051-014-2653-2