新型高效可见光响应BixOyClz光催化材料的合成与性能调控

The development of new type of visible-light-responsed photocatalyst is the focus in the field of photocatalysis. With the unique structural characteristics, BixOyClz system has highly efficient visible-light-responsed photocatalytic properties. In this project, novel BixOyClz photocatalyst will be prepared by hydrolysis -- high-energy ball milling -- middle temperature solid-state reaction method, which can reduce calcination temperature for metastable compounds. In order to optimize the performance of BixOyClz photocatalyst, Ag2O and 3d transition metal elements will be introduced. The main research contents are as follows: 1) By systematic experiments, the optimal process and raw material ratio will be decided. Mechanisms of controllable preparation and the relation among stoichiometric ratio, composition, microstructure and optical absorption properties will be studied. 2) The basic technique of Ag2O loading will be studied and optimized. And the influence of Ag2O loading on the photocatalytic properties will be obtained. 3) By introducing 3d transition metals into BixOyClz, the changes of electronic structures and the improvement of photocatalytic performance will be researched，the optimization technique and relative mechanisms will be obtained. 4) The preparation methods and optimization ways of BixOyClz will be applied into BixOyBrz and BixOyIz systems, and will be employed to the treatment of dyeing wastewater to decrease the chroma and chemical oxygen demand (COD).

开发新型可见光响应光催化材料是目前光催化领域的焦点。BixOyClz体系的独特结构奠定了开发高效可见光响应光催化材料的良好基础。本项目从降低煅烧温度开发介稳态化合物的角度出发，创新性地应用水解法--高能球磨辅助中温固相反应法制备新型BixOyClz可见光光催化材料，并引入Ag2O和3d过渡金属元素进行性能调控。主要研究内容：1)系统研究获得可控合成可见光响应BixOyClz的最佳工艺和原料配比，分析可控合成规律，探明计量比、组成和微观结构与其光吸收性能的关联规律。2)系统研究Ag2O可控负载的最佳工艺和相关规律，探明调控和优化原理。3)系统研究引入3d过渡金属对BixOyClz电子结构和光催化性能的影响，获得实现性能优化的最佳工艺。4)将可控合成工艺和优化途径推广于BixOyBrz和BixOyIz，并实际应用于处理印染废水，有效降低色度和化学需氧量(COD)。

开发和优化新型可见光响应光催化材料体系目前已经成为光催化领域的焦点问题，是决定光催化技术产业化应用的关键。新型氯氧化铋BixOyClz体系不仅拥有铋基化合物、层状结构、独特内建电场三大优势，而且其非计量比特性和沿C轴的超晶格结构也会带来带隙大小、光吸收性能、光量子效率的较大变化，都使其具有开发高效可见光响应光催化材料的良好基础。在国家自然科学基金的资助下，本项目掌握了可控制备BixOyClz和BixOyBrz光催化材料的关键技术-中温固相反应法，阐明了固相法制备工艺的基本规律。掌握了可控制备BixOyIz的关键技术-水热法，阐明了液相法制备工艺的基本规律。实现了采用中温固相反应制备了系列非化学计量比卤氧化铋介稳态化合物。材料的粒径在30-200 nm，最小可达到10 nm左右。在可见光辐照30分钟以内，催化剂用量为100 mg/100 ml时，对常见染料，如：MO、MB(10 mg/L)的COD去除率达92%，对苯酚类污染物的COD去除率达82%。获得Ag系化合物和BixOyClz复合后产物的可控制备与光催化活性调控，分析了性能优化机理。制备了3d过渡金属与BixOyClz复合后的四元化合物光催化材料Bi9V2ClO18，测试了其光催化性能。获得了四元化合物PbBiO2Cl、PbBiO2Br和Bi4NbO8Cl，测试了其光催化性能并进行了相关表征。实现了BixOyClz新型可见光光催化材料对印染废水的光催化降解并阐明了其降解机理。在此基础上，将性能优化的规律和在降解印染废水方面的应用推广到BixOyBrz和BixOyIz体系。本项目的研究结果使整个卤氧化铋体系在可见光光催化活性方面获得大的突破，可实际应用于高效污水处理。