Aurivillius phase Ca2Bi4Ti5O18 powders with micrometer size were produced by solidstate reaction. X-ray diffraction revealed that the powders had polar orthorhombic
structure with space group of B2cb. Ca2Bi4Ti5O18 ceramic exhibited frequency
independent dielectric anomaly at 774 °C. The piezoelectric coefficient d33 value of
poled Ca2Bi4Ti5O18 pellets was 0.7±0.2 pC/N. Both frequency independent dielectric
anomaly and detectable d33 value clearly indicated that Ca2Bi4Ti5O18 is a ferroelectric
material with Curie point of 774 ℃. UV–vis absorption spectra revealed that
Ca2Bi4Ti5O18 had a direct band gap of 3.2 eV. Photocatalytic activity of the
Ca2Bi4Ti5O18 powders was examined by degradation of rhodamine B (RhB) under
simulated solar light. 16% of RhB solution was degraded by Ca2Bi4Ti5O18 powders
after 4 h UV-vis irradiation. With Ag nanoparticles deposited on the Ca2Bi4Ti5O18 powders surface, 50% of RhB were degraded under the same irradiation condition. The
fitted degradation rate constant of Ag decorated Ca2Bi4Ti5O18 was 4 times higher than
that of bare Ca2Bi4Ti5O18. This work suggested that the Aurivillius ferroelectric
Ca2Bi4Ti5O18 is a promising candidate for photocatalytic applications
