0.75BiFeO 3 -0.25BaTiO 3 lead-free ceramics have been considered promising candidates for high-temperature piezoelectric applications. However, their dielectric and piezoelectric properties severely degrade with increasing temperature. In this work, improved dielectric and piezoelectric thermal stability was obtained in CuO-modified 0.75BiFeO 3 -0.25BaTiO 3 ceramics. CuO addition increases the volume fraction of the rhombohedral phase in the 0.75BiFeO 3 - 0.25BaTiO 3 ceramics and makes the chemical heterogeneity disappear. The dielectric and piezoelectric anomalies are eliminated near 300 °C and return with CuO additions, and the temperature degradations of the dielectric constant and piezoelectric coefficient of 0.75BiFeO 3 -0.25BaTiO 3 ceramics with 0.008 mol CuO in the range from 25 to 400 °C decrease by 85% and 60%, respectively. Furthermore, the depoling temperature and piezoelectric coefficient of 0.75BiFeO 3 -0.25BaTiO 3 ceramics with 0.008 mol CuO are 570 °C and 131 pC/N, respectively. These results indicate that CuO addition is an effective approach to improve both the dielectric and piezoelectric thermal stability of 0.75BiFeO 3 -0.25BaTiO 3 ceramics.
Wang Ziyang,Chen Peng,Shi Wenjing,Li Yang,Li Dequan,Zhang Leiyang,Yan Yan,Wang Yifei,Peng He,Li Quan,Liu Gang
In the current investigation, the CuO modified BaTiO 3 ceramics were prepared through the conventional electroceramic processing. XRD, XPS, and SEM have been employed to characterize the phases, valences of ions and the microstructures. The sintering behaviors of the prepared samples were performed using a dilatometer, and ceramics could be fabricated at lower temperature. The electric field and temperature dependent energy storage performance have been studied. The introducing of CuO is very effective to improve the energy storage density and the efficiency due to the formed double P-E loops. 0.5 wt.% CuO modified ceramic exhibited an energy density of 0.52 J/cm 3 , which is nearly twice of pure BaTiO 3 ceramic. The J-E loops of CuO modified samples indicated double domain switches, consistent with the double P-E loops.
Purpose This study aims to develop a copper oxide (CuO)-modified loofah biochar catalyst (CuO@LSC) for the activation of peroxymonosulfate (PMS), enabling the efficient degradation of C.I. Reactive Red 218 (RR218) in dye wastewater. Design/methodology/approach The study systematically examined the influence of various factors on the degradation of RR218, including initial pH, PMS concentration, CuO@LSC catalyst concentration, reaction temperature and the type and concentration of ionic species. Furthermore, the degradation mechanism of RR218 via free radical pathways was thoroughly investigated. Findings Under the conditions of 0.125 g/L CuO@LSC catalyst, 0.25 g/L PMS, at 25°C, and an initial pH of 9, a reaction time of 30 min achieved a degradation of up to 98.20%. Despite a 4.18-fold slowdown in dye degradation with sodium chloride (NaCl), the final degradation efficiency still reached 98%. In contrast, the addition of sodium sulfate (Na 2 SO 4 ) inhibited dye degradation, resulting in a degradation of less than 90%. Furthermore, the experimental results confirmed that dye degradation occurs due to the combined action of sulfate radicals (SO 4 •− ), singlet oxygen ( 1 O 2 ) and hydroxyl radicals (·OH). Originality/value This study successfully achieved the rapid treatment of dye wastewater, offering valuable insights for its recycling and reuse.
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