非金属掺杂Cu2(1-x)ZnxO/TiO2纳米管异质结构的构筑及其可见光制氢和催化性能研究

It is of great importance to realize the photocatalysts which can absorpt wide visible light to solve the energy and environmental problems. The syntheses and modifications of TiO2 tubular complex micro/nano-heterostructures are one of the cost-effective ways to expand their absorption abilities from UV light to visible light in order to produce hydrogen or degrade waste water. In this proposal, we will focus on the main problems, such as low quantum yield and wide band gap of TiO2 structures, and try to improve the fabrication methods and conditions, such as electrochemical-, hydrothermal/solvothermal- and sol-gel methods, etc, to get the visible-light-driven TiO2 structures with different tubular morphologies, dimensions and crystal structures. By modifying the TiO2 nano/micro- nanostructures with Cu2O, ZnO semiconductor in different components and non-metal elements(C,N,S) doping, we can improve the quantum yields, suppress the recombination of light generated hole-electron pair and adjust the band-gap to extend the light absorption from the UV region into the visible region. This novel non-metal doped Cu2(1-x)ZnxO/TiO2 tubular composites heterostructures can optimize the absorption of wide visible spectral, and achieve separation and transmission of light-generated carriers effectively based on the elements-doping and correlation effects of the oxide semiconductors. We further investigate the interface properties and level structures in order to improve the efficiencies of hydrogen production and wastewater degradation, and to explain the catalytic mechanisms of the heterostructures, which will provide experimental bases for their practical applications.

实现光催化材料对可见光的吸收在能源及环境治理等方面具有重要的意义，新型TiO2管状异质结构的制备及修饰是拓展其对可见光吸收进而提高太阳光制氢及污水降解经济有效的途径之一。本项目拟采用电化学、水热、溶胶凝胶等方法，针对TiO2管状结构量子产率低及带隙宽等问题进行研究，利用不同组分比的窄/宽带隙半导体(Cu2O、ZnO)对TiO2及其非金属元素(C、N、S)掺杂后的管状结构进行共修饰，以提高该复合异质结构的光量子化产率、抑制它的光生空穴电子对的复合率。这种新型的非金属元素掺杂的Cu2(1-x)ZnxO/TiO2管状异质结构，由于元素的掺杂可以调节其带隙宽度，加上半导体氧化物的共修饰，能实现对太阳光的吸收由紫外光拓展到可见光区，并有效实现光生载流子的分离与传输。我们进一步探索该异质结构的界面性质和能级结构，从而提高制氢及污水降解的效率，揭示异质结构的催化机理，为其应用提供实验基础。

以TiO2为代表的宽禁带半导体催化材料的太阳能利用率以及量子化效率比较低，这极大的限制了其在催化领域中的应用。为了提高光量子化产率、抑制它的光生空穴电子对的复合率，拓展了对太阳光的吸收范围，项目开展了如下工作：(a) 具有特定晶体结构、形貌的TiO2纳米管状结构及二元与三元金属氧化物的制备及性能研究；(b) 复合异质结构材料的构筑及其催化性能研究；(c) 掺杂复合异质结构的催化性能研究。在详细研究上述材料特性的基础之上，重点研究材料的催化效果及机理，项目最终实现了光谱吸收的拓宽、光生载流子分离效率的提催化效果的改善。本项目的研究结果对于催化材料的调控设计及催化机理的完善方面具有一定借鉴意义。