银@聚吡咯/质子钛酸盐可见光催化剂的制备及催化性能与机理研究

Developing visible-light photocatalysts with high efficiency and reusability, and applying them to the degradation of organic pollutants in sewage have important significance in environmental protection. In this project, based on the advantage of easy separation for protonic titanate (PT), we have designed a novel method to prepare Ag@polypyrrole (PPy)/PT visible-light photocatalysts, in which surface plasma resonance effect was used to improve the intensity of visible-light absorption; meanwhile, the p-n heterojunction was constructed for effective separation of photogenerated electrons and holes. According to the characteristic of redox reaction between conducting polymer monomer and noble metal salt, the Ag@PPy core/shell composites were decorated on PT nanostructures in one-step with the help of abundant negative charge on PT surface. Compared with traditional PT nanomaterials, Ag@PPy/PT novel photocatalysts solved the drawbacks of low visible-light absorption intensity and high combination efficiency between photo-generated electrons and holes at the same time. The photocatalytic activity of Ag@PPy/PT was evaluated by photodegradation of azo dye, and photocatalytic degradation mechanism was also illuminated during the study. This project not only explored a novel way to prepare the visible-light photocatalysts based on PT nanomaterials, but also provided theoretical and experimental evidence for Ag@PPy/PT visible-light photocatalysts using in treatment of organic wastewater; and hence, it had positive significance in the sewage treatments.

开发可重复利用的高效可见光催化剂来降解污水中的有机物，对环境保护具有重要意义。本项目针对这一课题，借助质子钛酸盐（PT）易分离的优点，设计了“利用表面等离子体共振效应提高材料可见光吸收的同时，构筑p-n异质结有效分离光生电子—空穴”的新思路，来制备Ag@聚吡咯（PPy）/PT可见光催化剂。我们利用导电高分子与贵金属盐之间氧化还原反应的特点及PT带有丰富负电荷的特性，“一步”制备Ag@PPy/PT复合材料。该材料的制备不仅可以解决传统PT材料可见光利用率低的问题，而且能够弥补光生电子—空穴复合几率高的不足。我们拟通过对偶氮类染料的降解，考察Ag@PPy/PT的可见光催化性能，阐明可见光降解机理。本项目的实施为基于PT可见光催化剂的构筑开辟了一条新途径，同时为Ag@PPy/PT可见光催化剂在污水处理方面的应用提供理论基础与实验依据，对水污染治理具有积极意义。

污水中有机物具有降解难、毒性高、积聚性强和流动性大等特点，对人类的健康和环境构成了严重威胁。针对这一课题，本项目利用表面等离子体共振效应提高材料可见光吸收的同时，构筑p-n异质结有效分离光生电子-空穴，通过“一步法”制备了Ag@聚吡咯（PPy）/质子钛酸盐（PT）可见光催化剂。相对于传统PT，该材料不仅有效解决了可见光利用率低的问题，而且改善了光生电子-空穴的分离几率，具有更高的可见光降解性能。同时，PT的大长径比提高了Ag@PPy/PT可见光催化剂的可循环利用性。受该材料降解机理启发，本项目还开展了基于g-C3N4表面等离子体共振可见光催化剂的制备及降解性能研究。与此同时，围绕有机污染物处理这一目标，我们以PPy为载体，通过负载磁性纳米粒子和贵金属纳米粒子，构筑了具有yolk/shell结构、破碎结构和分级多孔结构的多种磁性可循环利用催化剂，并对形貌、组成、催化活性、循环利用性，尤其是构效关系进行了详细研究，取得了一些积极成果。本项目的研究，为制备兼具优异降解活性和良好循环利用性的污水处理纳米材料提供了新的思路和方法，对我国水污染治理具有重要意义。