Role of bismuth in nano-structured doped TiO 2 photocatalyst prepared by environmentally benign soft synthesis Jir ˇı ´ Henych • Va ´clav S ˇ tengl • Martin Kormunda • Andreas Mattsson • Lars O ¨ sterlund Received: 2 December 2013 / Accepted: 24 January 2014 / Published online: 5 February 2014 Ó Springer Science+Business Media New York 2014 Abstract An environmentally benign synthesis method was used to prepare a nearly uniform dispersion of TiO 2 nanoparticles modified by bismuth for photocatalytic pur- poses. The role of bismuth in the catalyst structure was evaluated using numerous methods such as XRPD, HTXRPD, TEM and HRTEM, and XPS, as well as Raman, FTIR, and UV–Vis spectroscopy. The bismuth doping significantly improved the photocatalytic performance of azo dye RB5 discoloration due to the formation of surface Bi 3? species and the abundant hydroxylation of the catalyst surface. The great advantage of this procedure lies in the low temperature preparation under ambient pressure with- out use of the titanium organometallic precursors. There- fore, this developed synthesis procedure could be easily adapted to the industrial scale. Introduction Thanks to its properties, TiO 2 has been considered a very promising photocatalyst for many environmentally benign applications, including air and water treatment or water splitting. For common industrial uses, the development of a highly active, inexpensive and easy-to-prepare photocata- lyst is desirable. The widely used sol–gel methods mainly utilize titanium organometallic compounds as feedstocks, and the reactions occur in non-aqueous solvents, often at elevated temperatures and pressures, which causes the synthesis to be relatively expensive and burdensome to the environment. Other frequently used starting compounds include titanium chloride (TiCl 4 ) and titanium oxysulfate (TiOSO 4 ). However, TiCl 4 reacts highly exothermically with water and acids, which makes its handling difficult. In recent years, many studies have been conducted to enhance the activity of TiO 2 and its ability to utilize solar radiation. Some recent reviews have gathered information about the investigations and achievements of the prepara- tion of these so-called second-generation photocatalysts [1–3], where the methods of cation [4] or anion [5] doping, sensitization [6] and the formation of composites [7] have been extensively examined. Bismuth-doped titania appears to be a very promising material because bismuth itself forms highly photoactive compounds. The doping of titania or the formation of nanocomposites can therefore enhance the activity significantly. Many published works have used sol–gel synthesis to prepare Bi-modified TiO 2 that exhibits enhanced visible-light-activated degradation of various pollutants such as rhodamine B [8–10], the herbicide isoproturon [11], or the endocrine disruptor methylpara- thion [12]; synergic chromium (VI) reduction; and bisphe- nol A oxidation [13]. Co-doped systems are also a promising subject of research. Wang et al. [14] prepared a Electronic supplementary material The online version of this article (doi:10.1007/s10853-014-8083-9) contains supplementary material, which is available to authorized users. J. Henych (&)  V. S ˇ tengl Materials Chemistry Department, Institute of Inorganic Chemistry AS CR v.v.i., 25068 R ˇ ez ˇ, Czech Republic e-mail: henych@iic.cas.cz J. Henych Faculty of Environment, J.E. Purkyne ˇ University in U ´ stı ´ nad Labem, 400 96 U ´ stı ´ n. L., Czech Republic M. Kormunda Faculty of Science, J.E. Purkyne ˇ University in U ´ stı ´ nad Labem, 400 96 U ´ stı ´ n. L., Czech Republic A. Mattsson  L. O ¨ sterlund Department of Solid State Physics, The Angstro ¨m Laboratory, Uppsala University, 751 21 Uppsala, Sweden 123 J Mater Sci (2014) 49:3560–3571 DOI 10.1007/s10853-014-8083-9