耦合压电催化与半导体光催化的压电光催化技术是一种解决环境污染问题的高效手段。Bi_0.5Na_0.5TiO₃是一种钙钛矿结构的压电材料，已被广泛用于压电催化降解有机污染物。然而Bi_0.5Na_0.5TiO₃仍存在禁带宽度较宽，可见光响应较弱等不足。本论文采用水热法和静电纺丝技术，制备了不同形貌的Bi_0.5Na_0.5TiO₃/CdS异质结，通过对异质结的组成、结构、催化性能的表征，获得了高活性的催化剂。具体研究内容和结果如下：

（1）不同形貌Bi_0.5Na_0.5TiO₃的制备及光/压电催化性能研究。通过水热法和微波法制备了不同形貌的Bi_0.5Na_0.5TiO₃，表征测试了Bi_0.5Na_0.5TiO₃的形貌和组成，研究了不同形貌Bi_0.5Na_0.5TiO₃的光催化和压电催化性能。结果表明，水热法制备的Bi_0.5Na_0.5TiO₃纳米线结晶性更优，Bi_0.5Na_0.5TiO₃颗粒的压电催化性能更好，一阶动力学常数可达0.0397 min^-1。

（2）零维Bi_0.5Na_0.5TiO₃/CdS异质结的制备及压电光催化性能研究。通过水热法合成了CdS颗粒，CdS在Bi_0.5Na_0.5TiO₃表面均匀负载且结晶性良好，Bi_0.5Na_0.5TiO₃/CdS具有显著的可见光吸收性能，对降解RhB、MO和还原Cr(Ⅵ)溶液的一阶动力学常数分别为0.0951、0.0479和1.1359 min^-1，·O₂^-是压电光催化降解过程的主要活性物质。

（3）一维Bi_0.5Na_0.5TiO₃/CdS异质结的制备及压电光催化性能研究。通过静电纺丝技术和水热法制备了Bi_0.5Na_0.5TiO₃/CdS异质结。CdS颗粒均匀负载在Bi_0.5Na_0.5TiO₃纤维表面，Bi_0.5Na_0.5TiO₃/CdS异质结具有良好的结晶性和可见光吸收性能。Bi_0.5Na_0.5TiO₃/CdS对降解RhB、MO和还原Cr(Ⅵ)的一阶动力学常数分别为0.2054、0.0586和0.7470 min^-1，优于零维异质结的催化降解性能。

The piezoelectric photocatalysis technology, which couples piezoelectric catalysis with semiconductor photocatalysis, is an efficient means to solve environmental pollution problem. Bi_0.5Na_0.5TiO₃ is a piezoelectric material with the perovskite structure, which has been widely used for piezoelectric catalytic degradation of organic pollutants. However, Bi_0.5Na_0.5TiO₃ still has some shortcomings, such as wide band gap and weak visible light response. This paper uses hydrothermal method and electrospinning technology to prepare Bi_0.5Na_0.5TiO₃/CdS heterojunctions with different morphologies. By characterizing the composition, structure, and catalytic performance of the heterojunctions, highly active catalysts were obtained. The specific research content and results are as follows:

(1) Preparation of Bi_0.5Na_0.5TiO₃ with different morphologies and study on its photocatalytic/piezoelectric properties. Bi_0.5Na_0.5TiO₃ with different morphologies was prepared by hydrothermal and microwave methods. The morphology and composition of Bi_0.5Na_0.5TiO₃ were characterized and tested, and the photocatalytic and piezoelectric catalytic properties of Bi_0.5Na_0.5TiO₃ with different morphologies were studied. The results show that the Bi_0.5Na_0.5TiO₃ nanowire prepared by hydrothermal method has the better crystallinity, and the piezoelectric catalytic performance of Bi_0.5Na_0.5TiO₃ particles is better, with a first-order kinetic constant of 0.0397 min^-1.

(2) Preparation and piezoelectric photocatalytic performance study of zero- dimensional Bi_0.5Na_0.5TiO₃/CdS heterojunction. CdS particles were synthesized by hydrothermal method. CdS was uniformly loaded on the surface of Bi_0.5Na_0.5TiO₃ and exhibited good crystallinity. Bi_0.5Na_0.5TiO₃/CdS exhibited significant visible light absorption performance, with first-order kinetic constants of 0.0951, 0.0479, and 1.1359 min^-1 for the degradation of RhB, MO, and reduction of Cr (VI) solutions, respectively. ·O₂^- is the main active substance in the piezoelectric photocatalytic degradation process.

(3) Preparation and piezoelectric photocatalytic performance study of one-dimensional Bi_0.5Na_0.5TiO₃/CdS heterojunction. Bi_0.5Na_0.5TiO₃/CdS heterojunction was prepared by electrospinning technology and hydrothermal method. CdS particles are uniformly loaded on the surface of Bi_0.5Na_0.5TiO₃ fibers, and the Bi_0.5Na_0.5TiO₃/CdS heterojunction has good crystallinity and visible light absorption performance. The first-order kinetic constants of Bi_0.5Na_0.5TiO₃/CdS for the degradation of RhB, MO, and reduction of Cr (VI) are 0.2054, 0.0586, and 0.7470 min^-1, respectively, which are superior to the catalytic degradation performance of zero-dimensional heterojunctions.