Synthesis, crystal structure, and photocatalytic activity of a new two-layer Ruddlesden-Popper phase, Li2CaTa2O7

A new two-layer Ruddlesden-Popper phase Li2CaTa2O7 has been synthesized for the first time. The detailed structure determination of Li2CaTa2O7 performed by powder X-ray diffraction (XRD) and electron microscopy (ED) shows that it crystallizes in the space group Fmmm [a similar to 5.5153(1), b similar to 5.4646(1), c similar to 18.2375(3)angstrom]. UV-visible diffuse reflection spectrum of the prepared Li2CaTa2O7 indicates that it had absorption in the UV region. The photocatalytic activity of the Li2CaTa2O7 powders was evaluated by degradation of RhB molecules in water under ultra visible light irradiation. The results showed that Li2CaTa2O7 has high photocatalytic activity at room temperature. Therefore, the preparation and properties studies of Li2CaTa2O7 with a two-layer Ruddlesden-Popper structure suggest potential future applications in photocatalysis. (c) 2008 Published by Elsevier Inc.