The Ba 2+ doped ceramics of Ca 1−x Ba x Cu 3 Ti 4 O 12 (x = 0.005, 0.01, 0.03, 0.05 and 0.1) were sintered via conventional solid-state reaction at 1050 °C for 8 h in air. The microstructure and electric properties of Ba 2+ doping ceramics were investigated. The lattice parameters of Ca 1−x Ba x Cu 3 Ti 4 O 12 (CBCTO) ceramics decreased with the Ba 2+ doping, and Ba 1.31 Ti 8 O 16 as secondary phase was confirmed at x = 0.1. The doping of Ba 2+ resulted in uniformly distribution of small size grain (~4 μm). All the doped samples showed lower value of dielectric constant than CaCu 3 Ti 4 O 12 (CCTO), due to low resistivity of the grain boundary with the Ba 2+ doped samples. The nonlinear coefficient and breakdown field were significantly enhanced by Ba 2+ doping.
Mude Zhu,Yi Tang,Xueqin Chen,Biru Liao,Yang Yu,Sen Hou,Xiaoyun Fan
A built-in electric field of the ferroelectric contributes to improving the photoinduced charges separation in the photocatalysis, attracting great attention for the elimination of contaminants from water sources. Herein, a series of Ba 2+ doped Sr 1-x Ba x Bi 2 B 2 O 7 (0 ≤ x ≤ 0.6) were synthesized successfully. Among all samples, Sr 0.5 Ba 0.5 Bi 2 B 2 O 7 showing the most splendid photocatalytic degradation activity, could degrade 94.06% of TC in 30 min, which was about 6.75 and 2.56 times higher than that of the undoped one and BaTiO 3 , respectively. The synergistic effect of a strong built-in electric field and an appropriate oxygen vacancy was responsible for its high efficiency. The sample remained the superior photocatalytic activity under different reaction parameters including temperature, catalyst dosage, pH, initial ions species, and in the presence of humic acid and different types of water bodies. The different quenching and the controlled atmosphere experiments confirmed that e − and h + played an essential role in attacking TC molecular. LC-MS revealed its three degradation pathways including the process of demethylation, hydroxylation, and dehydroxylation. The toxicity of formed degradation products reduced significantly. The work is of great significance to construct more ferroelectric photocatalysts and highlights the potential of ferroelectric catalysts for purifying wastewater.
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