Hong Li,Xiao-Fang Jia,Qing Zhao,Ju-Ping Ma,Jian-Dang Liu,Bang-Jiao Ye,Yoshihiro Kuroiwa,Chikako Moriyoshi,Zhi-Yong Li,Qi Liu,Jun-Ying Zhang,Hong-Tao Sun
Graphical Beyond ferroelectricity : The defective [Bi 2 O 2 ] 2+ layers in Aurivillius phases show broadband near-IR luminescence that covers the telecommunication and biological optical windows (see figure). The luminescence was identified to stem from oxygen vacancies and defect complexes. This offers a probe for the examination of defect states in Aurivillius-phase ferroelectrics and possibilities for coupling both physical behaviors. Aurivillius phases have been routinely known as excellent ferroelectrics and have rarely been deemed as materials that luminesce in the near-infrared (NIR) region. Herein, it is shown that the Aurivillius phases can demonstrate broadband NIR luminescence that covers telecommunication and biological optical windows. Experimental characterization of the model system Bi 2.14 Sr 0.75 Ta 2 O 9− x , combined with theoretical calculations, help to establish that the NIR luminescence originates from defective [Bi 2 O 2 ] 2+ layers. Importantly, the generality of this finding is validated based on observations of a rich bank of NIR luminescence characteristics in other Aurivillius phases. This work highlights that incorporating defects into infinitely repeating [Bi 2 O 2 ] 2+ layers can be used as a powerful tool to space-selectively impart unusual luminescence emitters to Aurivillius-phase ferroelectrics, which not only offers an optical probe for the examination of defect states in ferroelectrics, but also provides possibilities for coupling of the ferroelectric property with NIR luminescence.
Aurivillius phases with narrow band gaps have attracted extensive interest in the field of photocatalysis, however, they exhibit poor activity due to the low utilization of photogenerated carriers. Herein, a series of S-scheme C3N4@Bi m+1 Fe m-3 Ti 3 O 3m+3 (m = 4, 5, 6) heterojunctions with two-dimensional structures were synthesized by simple two-step method. Compared with single materials, the composites exhibit excellent photocatalytic tetracycline degradation under visible light, and 91.8% of tetracycline can be degraded accompanied with 81.2% of TOC removal within 120 min over C 3 N 4 @Bi 5 FeTi 3 O 15 . The enhanced photocatalytic performance is due to strong interface interaction, high conductivity, and efficient charge separation ability. The mechanism analysis indicates that the C 3 N 4 @Bi 5 FeTi 3 O 15 heterojunction follows an S-scheme heterojunction mechanism with a strong interfacial internal electric field directed from C 3 N 4 to Bi 5 FeTi 3 O 15 , thus, the photogenerated electrons in Bi 5 FeTi 3 O 15 move toward C 3 N 4 , which retains high oxidation ability of Bi 5 FeTi 3 O 15 and high reduction ability of C 3 N 4 to efficiently produce the reactive species, such as O 2 − · and ·OH.
Graphical Abstract
危险品化学品经营许可证（带存储）