基于选择性光催化钛-铁基复合纳米材料协同降解机制研究

Starting from the regulation of the nano-composite structure with photochemical activity, a research proposal is presented to develop the current environmental materials mainly as dispersive particles loaded catalysts into nano-TiO2 and its nano-composite assembled structures to treat non-degradable pollutants in environment. Through regulating the composite structures of the TiO2-ZnO-Fe2O3 or FeOOH (Fe based oxides) on the nanometric scale, stable composite layers with different Ti/Fe ratios and mineral phase structures will be built on the substrates of SiO2 and SiC to synergistically generate coupling enhancement effects of visible light photocatalysis. The mechanisms of the regulation of TiO2-ZnO crystal phases and the structure of Fe-Ti oxides interface during the fabrication process are to be investigated. Efforts will be made to reveal the mechanisms of photo-catalytic oxidation degradation and selective photochemical removal of low concentration non-degradable pollutants in aqueous solution by the composite structures from the aspects of interfacial structure and interfacial chemistry, which will guide the optimization and enhancement of their sensitivity, removal ratio and stability towards target pollutants under photo-excitation. The research results will explore the intrinsic mechanisms followed by the special interactions between the nano-materials and low concentration non-degradable target pollutants in the co-existence of organic and inorganic substances, which will provide new theoretical basis and approach for the later stage modification and practical applications of the materials.

从调控具有光化学活性的纳米复合结构着手，提出将目前以分散型颗粒负载催化剂为主的环境材料发展为纳米结构TiO2材料及其复合纳米组装结构处理难降解环境污染物的研究。通过在纳米尺度上调控TiO2/ZnO -Fe2O3或FeOOH（铁基氧化物）的复合结构，在SiO2和SiC基底上构建不同Ti/Zn/Fe比和矿物相结构的稳固复合层，协同产生可见光催化耦合增强效应。研究制备过程中的TiO2-ZnO晶相调控机制及铁钛氧化物界面结构机理；力图从界面结构变化角度揭示此复合结构对水溶液中低浓度难降解污染物的光催化氧化降解和光化学选择去除机理。指导优化提高其光激发下对环境目标物的敏感性、去除率和稳定性。研究结果将探讨在有机/无机物共存条件下，纳米材料与低浓度、难降解目标污染物产生特殊相互作用所遵循的内在机制；从而为后期进一步的材料改性和实际应用找到新的原理和途径。

水环境污染问题长久以来是我国乃至全球面临的重大问题之一。传统水处理法无法完全有效地处理低浓度难降解污染物，利用光催化技术可以有效解决这个问题。光催化技术经过近半个世纪的发展，其在污染物治理方面的绿色高效性也逐渐被认可。本项目按计划开展了相关材料的制备、表征及性能研究的工作。制备了高效稳定的分子印迹TiO2，酸根离子修饰TiO2及羟基氧化铁复合材料。表征分析了不同表面改性方法对催化剂半导体特征及表面界面反应机理的影响。探究了表面修饰钛基材料的催化反应机制及界面结构机理，进一步阐明了材料的微观结构影响选择性吸附及催化过程的机制。深层次研究了分子印迹TiO2，硫酸根及碳酸根修饰TiO2，负载硫化银及氮化碳的表面修饰TiO2等复合材料的光催化选择性能与半导体材料表面界面特征之间的相互关系，探究了表面修饰状态与光催化的界面作用机制。分别用化学氧化法和溶胶-凝胶法合成了分子印迹TiO2，探究了分子印迹TiO2对污染物分子及其表面官能团的选择性特征，为揭示掺杂改性分子印迹TiO2光催化选择性理论研究及未来应用提供了新的思路。采用稀硫酸作为抑制剂合成SO42-/TiO2材料，SO42-成功增强了TiO2材料的选择吸附性能，从而协同光催化过程实现选择性消除目标污染物。采用水浴加热回流的方法制备了α-FeOOH和α-FeOOH/石墨烯（GO）复合材料，有效提高了α-FeOOH/GO的表面电荷转移效率。从而为提升α-FeOOH/GO结构性能调控基础研究提供指导。.目前，课题组发表国内外论文24篇,申报2项专利。项目成果对选择性修饰TiO2及FeOOH复合材料的微观界面选择性机理、结构性能调控机制阐明具有重要意义。