镓酸铋活性晶面与氧空位的共构筑及其可见/近红外光催化净化水中抗生素机理研究

Toxic and refractory antibiotic pollutants in water could threaten to human health and ecological system. Traditional treatment technologies such as adsorption, membrane separation and biological treatment are not effective and easy ways to remove antibiotic pollutants. Thus, it is very meaningful to develop new water treatment technologies for the removal of antibiotic pollutants. As a new water treatment technology, photocatalysis possesses many advantages such as high efficiency, mild reaction conditions and easy-operation. The photocatalytic activity is a key factor for the large-scale practical application of photocatalysis technology. In order to obtain high efficient visible and near-infrared responsive bismuth gallate photocatalysts, exposed high-active crystal facet engineering and oxygen vacancy engineering are scheduled to adjust the band structure and surface atomic arrangement of photocatalysts for the improvement of their photocatalytic activity and light adsorption property in this project. The influences of exposed facets and oxygen vacancies on the band structure, surface atomic arrangement and light adsorption property of photocatalysts will be discussed in detail on the base of the characterizations and density functional theory. In the photocatalytic process, the mechanism among the exposed facets, oxygen vacancy and antibiotic pollutants will be investigated. This project could provide some theory evidences for the application of photocatalytic removal of antibiotic pollutants in water.

水体中有毒难降解抗生素污染物威胁着人类健康和生态环境平衡，传统处理技术如吸附、膜分离和微生物处理等存在效率低、处理条件要求高等缺点，因此探索用于净化抗生素污染物的新型水处理技术具有重要的现实意义。光催化技术是一种新型的水处理技术，具有效率高、反应条件温和、操作简单等优点，限制其实际应用的关键因素是光催化剂的活性。本项目拟通过活性晶面和氧空位的共构筑来调控光催化剂的能带结构和表面原子排布等，进而提高其光催化活性和光谱吸收范围，最终获得高活性高稳定性可见/近红外光响应的镓酸铋光催化剂。同时，结合多种表征技术和密度泛函理论计算，探讨晶面和氧空位共构筑对镓酸铋能带结构、表面原子排布和光谱吸收范围等的影响规律，揭示镓酸铋活性晶面、氧空位和抗生素污染物三者之间的作用机制，为光催化技术应用于处理水体中抗生素污染物提供理论依据。

水体中广泛存在的有机污染物（如抗生素和染料等）和重金属离子威胁着人类健康和生态平衡，其处理技术仍是水污染控制领域的研究热点之一。本项目成功制备了多种新型的可见光或近红外光响应的Bi基光催化材料，重点研究了材料微结构对其光催化活性的影响机制。项目研究内容主要包括三个方面：（1）合成了暴露{110}活性晶面的Bi2Ga4O9纳米片，结果表明当AgI负载量为25%时，AgI/Bi2Ga4O9 p-n结复合物具有最佳的光催化活性。光电化学测试证实AgI/Bi2Ga4O9 p-n结的形成显著促进了光生电子和空穴的分离与迁移，进而提高了超氧自由基的产量，最终导致光催化活性的增强。密度泛函理论计算结果表明AgI/Bi2Ga4O9 p-n结的形成促进了光生电子从AgI转移到Bi2Ga4O9，并结合实验结果提出了AgI/Bi2Ga4O9 p-n 结复合物可见光催化降解有机污染物的机制。（2）结合理论计算和实验表征结果表明Bi4O7纳米片中Bi5+和氧空位的协同作用不仅缩小了带隙宽度，拓展了光谱吸收范围，而且提高了载流子的分离效率，最终显著提高了光催化活性。此外，系统研究了Bi4O7纳米片光催化降解环丙沙星抗生素和罗丹明B染料污染物的中间产物、反应路径，进而提出了Bi4O7纳米片可见/近红外光催化降解有机污染物的机制。（3）系统研究了氧掺杂BiSI（O-BiSI）纳米棒合成过程的影响因素，并利用电子顺磁共振、X射线光电子能谱、X射线近边结构谱和扩展的X射线吸收精细结构谱等证实了BiSI纳米棒中氧掺杂和硫空位的存在有利于其对Cr(VI)的吸附和近红外的吸收及光生载流子的分离。最后，基于一系列表征测试和密度泛函理论计算分析了O-BiSI光催化还原Cr(VI)的反应动力学过程。本项目的研究不仅为去除水体中抗生素和染料污染物提供新的思路，而且为开发近可见/红外光响应的光催化材料提供理论依据。