Ferroelectric and photocatalytic properties of Aurivillius phase Ca₂Bi₄Ti₅O₁₈

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

Relaxor ferroelectric and photocatalytic properties of BaBi4Ti4O15

Aurivillius phase BaBi4Ti4O15 micro-sized powders were produced by solid-state reaction and their photocatalytic properties were reported for the first time. X-ray diffraction revealed the polar orthorhombic structure. BaBi4Ti4O15 ceramics exhibited diffuse phase transition at ~ 410 C. The freezing temperature of 274 C was obtained by fitting the Vogel-Fulcher law. The distinct ferroelectric domain switching current peaks in current - electric field (I-E) loop and piezoelectric coefficient d33 value of 7.0  0.1 pC/N at room temperature further demonstrated relaxor ferroelectric behavior of BaBi4Ti4O15. UV-vis absorption spectra indicated that BaBi4Ti4O15 had a direct band gap of 3.2 eV. The photocatalytic study showed 15 % degradation of Rhodamine B (RhB) solution by BaBi4Ti4O15 powders after 3.5 h UV-vis irradiation. The RhB degradation rate was further enhanced by depositing Ag nanoparticles on the BaBi4Ti4O15 powders surface. This work suggested that the relaxor ferroelectric BaBi4Ti4O15 is promising for photocatalytic applications

Relaxor ferroelectric and photocatalytic properties of BaBi4Ti4O15

Aurivillius phase BaBi4Ti4O15 micro-sized powders were produced by solid-state reaction and their photocatalytic properties were reported for the first time. X-ray diffraction revealed the polar orthorhombic structure. BaBi4Ti4O15 ceramics exhibited diffuse phase transition at ~ 410 C. The freezing temperature of 274 C was obtained by fitting the Vogel-Fulcher law. The distinct ferroelectric domain switching current peaks in current - electric field (I-E) loop and piezoelectric coefficient d33 value of 7.0 0.1 pC/N at room temperature further demonstrated relaxor ferroelectric behavior of BaBi4Ti4O15. UV-vis absorption spectra indicated that BaBi4Ti4O15 had a direct band gap of 3.2 eV. The photocatalytic study showed 15 % degradation of Rhodamine B (RhB) solution by BaBi4Ti4O15 powders after 3.5 h UV-vis irradiation. The RhB degradation rate was further enhanced by depositing Ag nanoparticles on the BaBi4Ti4O15 powders surface. This work suggested that the relaxor ferroelectric BaBi4Ti4O15 is promising for photocatalytic applications

Additional file 1 of Antimicrobial resistance survey and whole-genome analysis of nosocomial P. Aeruginosa isolated from eastern Province of China in 2016–2021

Supplementary Material 1: Bacterial information in this articl

Relaxor behavior and photocatalytic properties of BaBi2Nb2O9

Lead‐free Aurivillius phase BaBi2Nb2O9 powders were prepared by solid‐state reaction. Ferroelectric measurements on BaBi2Nb2O9 (BBNO) ceramics at room temperature provided supporting evidence for the existence of polar nanoregions (PNRs) and their reversible response to an external electric field, indicating relaxor behavior. The photocatalytic degradation of Rhodamine B reached 12% after 3 hours irradiation of BBNO powders under simulated solar light. Silver (Ag) nanoparticles were photochemically deposited onto the surface of the BBNO powders and found to act as electron traps, facilitating the separation of photoexcited charge carriers; thus, the photocatalytic performance was significantly improved. The present study is the first examination of the photochemical reactivity of a relaxor ferroelectric within the Aurivillius family with PNRs

Terahertz Faraday Rotation of SrFe₁₂O₁₉ Hexaferrites Enhanced by Nb Doping

The magneto-optical and dielectric behavior of M-type hexaferrites as permanent magnets in the THz band is essential for potential applications like microwave absorbers and antennas, while are rarely reported in recent years. In this work, single-phase SrFe12–xNbxO19 hexaferrite ceramics were prepared by the conventional solid-state sintering method. Temperature dependence of dielectric parameters was investigated here to determine the relationship between dielectric response and magnetic phase transition. The saturated magnetization increases by nearly 12%, while the coercive field decreases by 30% in the x = 0.03 composition compared to that of the x = 0.00 sample. Besides, the Nb substitution improves the magneto-optical behavior in the THz band by comparing the Faraday rotation parameter from 0.75 (x = 0.00) to 1.30 (x = 0.03). The changes in the magnetic properties are explained by a composition-driven increase of the net magnetic moment and enhanced ferromagnetic exchange coupling. The substitution of the donor dopant Nb on the Fe site is a feasible way to obtain multifunctional M-type hexaferrites as preferred candidates for permanent magnets, sensors, and other electronic devices