Rapid synthesis of ultratine K2Ln2Ti3O10 (Ln = La, Nd, Sm, Gd, Dy) series and its photoactivity

Ultrafine-layered lanthanon titanates K(2)Ln(2)Ti(3)O(10) (Ln = La, Nd, Sm, Gd, Dy) were fabricated at relatively low temperature by a stearic acid method (SAM). The obtained products were characterized by FT-IR, X-ray diffractometer, DTA-TG, scanning electron microscopy, transmission electron microscopy and BET experiments. The photocatalytic activity of the obtained products was studied and was compared with that of solid-state reaction (SSR) using photodecomposition of methyl orange as the model system. Results showed that by using SAM, the fabricating temperature was lowered (from 1100 to 800 degrees C and the reacting time was shortened (from at least 11-2 h). Comparing with the product of traditional SSR, the particle size of K(2)Ln(2)Ti(3)O(10) synthesized by SAM is smaller, BET surface area is higher (more than 16.97 m(2)/g), and photoreactivity is better. It was very interesting to find the difference in d(002) of obtained K(2)Ln(2)Ti(3)O(10) for Ln = La, Nd, Sm, Gd., Dy separately and the photoactivity of K(2)Ln(2)Ti(3)O(10) is strongly dependent on lanthanide, increasing in the sequence of La < Sm < Nd < Gd < Dy. A possible reason was put forward. (c) 2004 Elsevier Inc. All rights reserved.