Hydrothermal crystallization of bismuth oxybromide (BiOBr) in the presence of different shape controlling agents
Enikő Bárdos, Viktória Márta, Lucian Baia, Milica Todea, Gâbor Kovács, Kornélia Baán, Seema Garg, Zsolt Pap, Klára Hernádi
Abstract
Bismuth oxybromide samples were synthesized using solvothermal crystallization and different additives (CTAB-cetyltrimethylammonium bromide, PVP–polyvinylpyrrolidone, SDS–sodium dodecyl sulfate, U–urea and TU–thiourea). The effect of the mentioned compounds was investigated through structural (crystallite size, crystal phase composition, etc.), morphological (crystal shape), optical (band gap energy) parameters, surface properties (surface oxidation states), and the resulting photocatalytic activity. It was found that the ratio of the (1 0 2)/(1 1 0) crystallographic planes, the presence of oxidized Bi4+ and Bi5+ species were responsible for the obtained photocatalytic activity. Moreover, a strong dependency was revealed between the surface tension of the shape tailoring agents and the overall morpho-structural parameters, pointing out the fact that the properties of the semiconductor can be more easily tuned using the surface tension modification as a tool.