晶面取向可控的BiOClnBr1-n超薄纳米片制备及光催化性能研究

This proposal aims to introduce crystal facets orientation controllable growth and alloyed bismuth oxyhalides into ultrathin BiOX nanosheets system. Using hydrothermal self-assembly method and mechanical stripping technology, realizing crystal facets control fabrication of ultrathin BiOClnBr1-n nanosheets. Due to the controllability of crystal facet and chlorine and bromine compostion; it is possible to enhance the catalytic activity of the greatest degree. We will evaluate the photocatalytic degradation ability of such BiOClnBr1-n catalyst for EDCs under visible light, and hope to solve some technical problems, such as poor catalytic activity, low mineralization rate and so on. The different crystal facets and diferent chlorine and bromine compostion for reaction time and catalyst activity in decomposition of EDCs will be explored. By using density functional theory computations and molecular dynamics simulations, we can find the optimal combination of these catalysts, showing the best catalytic activity, and study the catalytic mechanism. Through evaluate the photocatalytic degradation ability of such catalyst for EDCs, adjust the synthetic strategy, prepare catalyst with excellent stability and high catalytic degradation ability for EDCs. We believe that related results will have a positive influence to the development of high-performance heterogeneous photocatalyst.

本项目意在将晶面取向可控生长和多元卤素效应同时引入BiOX超薄纳米片体系，利用水热法及机械剥离技术，制备晶面取向可控的BiOClnBr1-n超薄纳米片催化剂。这类催化剂由于晶面取向和氯、溴组成均可调控，因而其催化活性能够得到大幅度提升且能充分体现。我们将研究这类催化剂在可见光下对内分泌干扰物（EDCs）的催化降解效果，期望为解决半导体对水体中EDCs光催化降解活性差，矿化率低的难题提供依据。探讨不同晶面取向，不同氯、溴组成与催化降解EDCs催化活性及矿化率的相互关联；利用第一性原理计算和分子动力学模拟寻找BiOClnBr1-n中晶面取向与氯、溴组成的最佳组合，究析催化机理。根据实验数据调整合成方案，最终获得对EDCs具有高效率催化降解能力且可多次重复使用的BiOClnBr1-n超薄纳米片催化剂产品。我们认为，本项目的研究有望对高效能非均相光催化剂的发展产生积极的促进作用。

本项目针对BiOClnBr1-n超薄纳米片的制备和其在光催化水体净化应用中需要解决的关键科学问题，系统研究了制备工艺对材料主导暴露晶面和厚度的影响，运用新型表征手段分析了材料结构，建立了合成工艺与材料微结构间的联系，实现了BiOClnBr1-n超薄纳米片的晶面取向可控制备。动态分析并揭示了合成过程中反应参数诱导的各阶段固相样品微结构与液相成分的变化规律，揭示了超薄纳米片构建基础上的晶面取向可控制备机理，为光催化材料的可控制备提供了理论和实验依据。采用理论计算和实验相结合的方式，阐明了晶面取向-多元阴离子效应-光催化性能三者间的联系，理清了晶面取向和多元阴离子效应诱导材料光催化性能增强的影响作用机制。将催化剂应用于水中EDCs的去除，确立了材料微结构与EDCs光降解性能的构效关系，为该材料从理论研究走向实际应用指明了方向。在完成本项目指定研究内容的基础上，还开展了催化剂表面缺陷结构形成机理、复合材料组分比例对光催化性能影响机制等方面研究，取得了一定成果。在本项目的资助下，项目负责人以第一或通讯作者身份在Applied Catalysis B: Environmental，Environmental Science & Technology，Nano Research，Journal of Hazardous Materials，The Journal of Physical Chemistry C和ChemPhotoChem等期刊发表标明项目编号的SCI论文6篇，其中1篇论文被选为当期Cover Feature。申请国家发明专利3项，参与国际国内会仪7次。