Ferroelectric ceramics (BaTiO₃_MnO₂) with different Mn admixtures were prepared using solid-state synthesis. Elemental analysis, powder X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, and impedance spectroscopy confirmed that the BaTiO₃ and MnO₂ coexisted in the ceramics. In addition, the high purity and homogeneity of the element distributions in the ceramic samples were confirmed. The adsorptive and photocatalytic properties of the BaTiO₃ (reference sample, BTO) and BaTiO₃_MnO₂ materials (BTO_x, where x is wt.% of MnO₂ and x = 1, 2 or 3, denoted as BTO_1, BTO_2 and BTO_3, respectively) were evaluated using Rhodamine B (RhB) as the model dye in a photocatalytic chamber equipped with a UV lamp (15 W) in the absence of additional oxidants and (co)catalysts. No adsorption of RhB dye was found for all the materials during 360 min (dark experiment). All samples were photocatalytically active, and the best results were observed for the BTO_3 material, where RhB was 70% removed from aqueous solution during 360 min of irradiation. The photodegradation of RhB in the presence of MnO₂-modified BTO ceramics followed a pseudo-first order model and the rate constant of BTO_3 was about 10 times higher than that of BTO, 2 times that of BTO_2, and 1.5 times that of BTO_1. The photocatalysts could be successfully reused after thermal activation.

The BaZr_xTi_1-xO₃ for 0⩽x⩽15 ceramics were prepared by a conventional solid state reaction method and were determined by an X-ray diffraction (XRD) and scanning electron microscopy (SEM) for crystallographic, surface morphological and compositional studies. A single phase with perovskite structure was identified in the samples at room temperature. No significant impurities were detected in an EDS spectrum and the samples are in good stoichiometric ratio. The temperature dependence of electric conductivity was evaluated in the temperature range from 300 to 550 K for a selected frequency by a HP4284 LCR meter. The activation energy was calculated from the Arrhenius plots.

The differences between the physical properties of barium titanate BaTiO3 and newly obtained BaHfxTi1-xO3 were identified. These ceramics were prepared by solid-phase reaction from simple oxides and carbonates using the conventional method. The structure and morphology of investigated samples were characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The application of impedance spectroscopy made possible to characterize of these materials in the terms of electrical properties.

A lead-free solid solution Ba_0.80Sr_0.20Ti_0.75Zr_0.25O₃ was prepared by a conventional technology. The structure and morphology of investgated samples were characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The studies of electric conductivity were performed depending on temperature and frequency of electric measuring field. The activation energy was calculated from the Arrhenius plots.