生物分级构型纳米多孔金属光催化材料制备及构效关系研究

Photocatalysis material research is a research hotspot of material science. The unsatisfied light-harvesting and carrier-mobility of traditional semiconductor photocatalysis material restrict further improvement of the catalyst performance. The introduction of high catalytically active and carrier-mobility nanoporous metal and high light capture biomimetic hierarchical structure into traditional semiconductor will improve its quantum yield. This project proposes to use biomimetic hierarchical structure as the basis to establish nano-porous metal structure, on which the ternary oxide nano dots with highly catalytic activity are compounded to prepare the photocatalyst with high efficiency of light trapping and photon conversion. Explore the evolution of biomimetic hierarchical nanoporous metal microstructures during fabrication. By the study of the structure-activity relationship between the biomimetic hierarchical nanoporous metal structure parameters and the efficiency of light trapping and photon conversion, the influence rules between reaction conditions and photocatalytic performance, the mechanism of the high photocatalytic activity possessed by the compounded material can be revealed. The structural and performance design of the photocatalyst with high efficiency of light trapping can be achieved, then put forward the design principle of high efficient photocatalysis material, which also provides the theoretical and technical reference for the further research and development of photocatalytic with high-performance on photocatalytic decomposition of water.

高效光解水催化材料是材料领域的研究热点。传统半导体光催化材料的光捕获率和载流子迁移率有待提高，制约了其催化性能的进一步提升。而在半导体材料中引入具有高光捕获的仿生分级结构和高催化活性、高载流子迁移率的纳米多孔金属，有望提高其量子产率。本项目提出以仿生分级结构作为骨架构筑纳米多孔金属结构，并在其基础上复合高催化活性的三元氧化物纳米点，制备具有高光捕获和催化活性的光解水催化材料。并探究仿生分级纳米多孔金属在制备过程中的组织演变规律。通过研究其结构参数与光捕获率和量子产率之间的构效关系、以及催化反应条件对其光催化性能的影响规律，揭示该仿生分级纳米多孔光解水催化材料的催化机制，进而提出高效光催化材料的设计准则。为进一步开展高性能光解水催化材料的研究开发提供实验和理论参考。

光催化原理是利用半导体中光致激发的电子和空穴参与表面的氧化还原反应，光催化的效率由光捕获效率、载流子分离迁移效率、表面反应效率控制。为了提高量子产率，一方面通过调控和改变表面形貌提高其光捕获效率；另一方面，通过催化材料的材质开发和结构设计等途径促进光生载流子的有效分离。仿生纳米多孔结构具有优异的光吸收性能，将半导体纳米点与该结构进行复合，并在其上构筑异质结结构，有望制备出具有高效光催化性能的材料，为开发新型高效光催化材料提供理论指导和实践探索。.基于上述理念，我们通过制备工艺的优化，利用溶胶凝胶法成功制备了仿生分级多孔异质结光催化材料。我们对其进行结构表征，证实合成了3D/2D分级的多孔异质结复合材料。利用紫外-可见漫反射光谱研究其吸光性能，结果表明该复合材料的光吸收性能相较无蝶翅模板的样品有明显提升。在可见光条件下测试其光催化降解苯酚的能力，实验结果表明该复合材料相较对比样品具有最优异的降解性能，为无异质结对照样品的9.9倍，为无仿生多孔结构对照样品的1.9倍，在4小时内能够降解60 %浓度的苯酚溶液。进一步地，我们建立了催化性能与结构之间的构效关系。我们利用光电化学测试、光致发光光谱、电子顺磁共振进一步地研究了其降解机理，证实了我们所制备的仿生分级多孔异质结催化材料能够有效抑制载流子的复合，促进光吸收。这项工作证实了了仿生分级多孔结构对于光子的捕获作用，为后续深入探索仿生分级多孔金属光催化材料奠定了实验基础并提供了理论指导。