( )Ferroelectric and photoelectrochemical studies of lead-free Ba0.925Bi0.05 square(0.025)(Ti0.05Zr0.30Sn0.05)O-3 ceramic and its application to Rhodamine B oxidation under solar light
Résumé
New materials with general formula Ba0.925Bi0.05 square(0.025)(Ti0.05Zr0.30Sn0.05)O-3 (symbolized BBiTZS) were prepared by high-temperature solid-state reaction. The room X-ray diffraction pattern suggests a cubic perovskite structure. The thermal variation of the permittivity at different frequencies showed a relaxor ferroelectric behavior. The Raman spectroscopy was in accordance of the dielectric measurements. The diffuse phase transition parameters were determined from the modified Curie-Weiss law, while the relaxor behavior was highlighted by a good fit to the Vogel-Filcher relationship. The capacitance-potential (C-sc(-2) - E) graph at pH similar to 7 is characteristic of n-type behavior with a flat band potential (E-fb) of -0.52 V-SCE and an electron density (N-A) of 2.7 x 10(18) cm(-3). The Electrochemical Impedance Spectroscopy, measured in the region (1 mHz - 10(5) Hz), showed a semicircle, assigned with the bulk property (27 k Omega cm(2)); a constant phase element (CPE) is responsible for the depletion angle (-9 degrees). With an optical of 2.00 eV, the ferroelectric BBiTZS possesses appealing photocatalytic capability and was successfully experimented for the oxidation of Rhodamine B (Rh B) exposed to solar light. According to the band diagram, electrons from the conduction band of BBiTZS are injected into dissolved oxygen, resulting in O-2 center dot radicals, which are employed in the Rh B oxidation. UV-Visible spectrophotometry was used to follow the Rh B discoloration. On a solar irradiation of 97 mW cm(-2), a conversion of 50% is achieved in Rh B solution (10 mg L-1) within 100 min., and the degradation follows a first order kinetic model with a half photocatalytic-life of 90 min. (C) 2022 Published by Elsevier B.V. on behalf of King Saud University.