非晶态-晶态纳米同质异相结的构筑与太阳光谱响应光催化材料研究

Photocatalyst material has been a widely discussed topic in converting the photon energy to chemical energy at the forefront of environment and energy research fields. According to the key scientific issues of high-efficiency generation and mobility of photo-generated carrier, this project puts forward an innovation scheme within construction of amorphous-crystalline nano-heterogeneous-homojunction. It can simultaneously accomplish purposes of wide frequency response and high efficient separation of electron hole by band-gap narrowing, built-in electric field and the unique electronic transmission interface. Hydroxyls are injected into nano metal oxides crystal lattices through sonochemistry in liquid phase, inducing the disordered crystal facets based on the selected protection. This method meets the aim that high performance photocatalytic materials with the structure of analogous schottky junction are synthesized. The physics and chemistry methods on crystal facets selective disordering are investigated. Furthermore, the influence on oxygen vacancy, band structure, spectral response and photocatalytic properties by hydroxylation degree, amorphous layer thickness and crystal facets selecting are studied. Then, the unique electronic structure and defects on the interface of amorphous-crystalline are unveiled, solving its impacts on carriers transport and recombination on interface. Finally, a new photocatalysis theoretical model of nano-heterogeneous heterojunction is established. This project provides a new approach for the research and development of nano-heterojunction photocatalytic materials, which is expected to achieve a breakthrough in photocatalytic materials with high-efficiency solar spectral response.

利用光催化材料实现太阳能-化学能的高效转化是当前环境和能源领域的科学研究前沿。根据光催化材料的光生载流子高效产生与有效迁移等关键科学问题，项目提出构筑一种非晶态-晶态纳米同质异相结，利用带隙窄化、异相结内建电场与电子传输特性界面同步实现电子空穴的宽频响应与高效分离的创新方案：采用声化学羟基注入诱导金属氧化物纳米晶表面无序化的方法，基于晶面的选择性保护，实现纳米晶特定晶面的选择性无序化，从而制备出具有类肖特基异质结结构的高效光催化材料。项目拟研究实现晶面选择性无序化的物理化学方法；研究羟基化度、非晶层厚度、选择晶面等对氧空位、能带结构、光谱响应和光催化性能影响等相关规律；研究非晶态-晶态界面独特的电子结构与缺陷行为及其对载流子迁移与界面复合影响的内秉机制，建立新型纳米同质异相结的光催化理论模型。本项目为纳米异质结光催化材料的研制开发提供了新思路，可望实现高效太阳光谱响应光催化材料的重点突破。

利用光催化材料将太阳能直接转化为化学能在环境与新能源领域意义重大，受到了广泛关注。本项目围绕纳米半导体的光生载流子高效产生与有效迁移等关键科学问题展开。主要研究成果概论如下：设计合成了一系列新型非晶态-晶态金属氧化物纳米同质异相结，掌握了纳米同质异相结中非晶态-晶态界面、氧空位、金属离子价态和无序化度的调控方法与变化规律，研究了该异相结的能带结构、界面载流子传输特性以及其对光催化性能的影响，掌握了其光激发、电子迁移与无序化度之间的关系与影响规律，实现了提升金属氧化物纳米同质异相结的光催化量子转换效率和实现太阳光宽光谱利用的目的，获得了几种新型非晶态-晶态金属氧化物纳米同质异相结高性能光催化材料；项目还开展了新型宽带隙CeF3基纳米异质结光催化材料的研究，构建了非金属离子O、N掺杂的CeF3、高浓度非金属离子O掺杂的CeF3O、Ag/CeF3O异质结、O,N-CeF3/α-FeOOH异质结等几种新型光催化材料，实现了带隙窄化和太阳光谱的高效利用，将光谱响应范围拓展到近红外波段，促进了光生载流子空间上的定向分离和迁移，使得其在可见光和近红外光下表现出优秀的光催化产氧活性和降解盐酸四环素等有机污染物的性能。此外，项目还研究建立了g-C3N4/TiO2/C纳米异质结太阳光催化材料的水热原位制备技术，构筑出了适用于光催化降解水体有机污染物的高性能、低成本太阳光谱响应光催化材料，极具应用推广价值。在本项目资助下，目前已发表SCI期刊论文12篇，参加国内外学术会议3人次，获得授权国家发明专利8项、申请国家发明专利1项；培养博士研究生2名，硕士研究生6名。项目投入直接经费60.0万元，间接经费10.4万元。执行期间内项目直接经费实际支出40.30万元，各项支出基本与预算相符。结余经费19.70万元，这些款项将用于该项目的后续研究工作。