基于石墨烯量子点复合材料的高效增强可见光催化性能研究

This topic aims to controlled preparation and visible-light catalytic properties of new multi-composite materials based on graphene quantum dots (GQDs). water-soluble GQDs were prepared by a simple hydrothermal method, and used to modify silver vanadate nanoparticles. GQDs can enhanced visible light photocatalytic efficiency of silver vanadate nanoparticles using the electron transfer and good response to visible light characteristics. Meanwhile, GQDs modified silver vanadate nanoparticles combined with the noble metal nanoparticles can be further enhanced photocatalytic efficiency, due to the noble metal nanoparticles have local surface plasmon resonance effects. The visible light responce regulatory role and mechanism of co-modified photocatalyst were investigated. The structure and chemical composition of silver vanadate nanocomposites were characterized by conventional and high resolution methods, revealing the visible light photocatalytic influence factors by microstructure (size, morphology, crystalline condition, surface defects, surface functionalization, etc.), the component, optical properties and local surface plasmon resonance effects, clarifying visible light photocatalytic enhancing mechanisms of univariate and multivariate compounds of silver vanadate. A novel GQDs and noble metal nanoparticles were sub-regulated photocatalytic properties of silver vanadate nanoparticles, which is expected to be an important application in the degradation of pollutants and water splitting, but also providing a theoretical foundation for the design and development of excellent performance, widely usage of multifunctional nanocomposites.

本课题旨在开展基于石墨烯量子点的一种新型多元复合材料的可控制备及其可见光催化性能研究。用简易的水热法制备水溶性石墨烯量子点，并用它修饰钒酸银纳米粒子，利用石墨烯量子点的电子转移和可见光响应等特性调控钒酸银纳米粒子在可见光范围内的光催化效率；再结合贵金属纳米粒子的局域表面等离子体共振效应，将贵金属纳米粒子与石墨烯量子点共修饰钒酸银纳米粒子，研究共修饰对可见光范围内光催化性能的调控作用及其机理。采用常规和高分辨手段对钒酸银纳米复合材料的结构与化学成分进行表征，揭示微结构（尺寸、形貌、结晶状况、表面缺陷、表面功能化等）、组分、光学性能、局域表面等离子体共振效应对可见光光催化性能的影响规律，在此基础上澄清两元和多元复合对钒酸银纳米材料可见光光催化性能增强的物理化学作用机制。本工作用新颖的石墨烯量子点与贵金属纳米粒子系统调控钒酸银纳米粒子的光催化特性，有望在污染物降解和劈裂水制氢等领域获得重要应用。

在众多光催化剂中，钒酸银纳米粒子由于其在可见光范围内具有响应能力，是一种优良的光催化剂。然而钒酸银纳米粒子在光催化反应中，空穴与光生电子容易复合，成为阻碍其商业应用的难题。为解决钒酸银纳米粒子在空穴与光生电子容易复合的难题，在本项目支持下，发展一种新颖的环境友好的多元复合纳米结构体系——石墨烯量子点和多种贵金属纳米粒子共修饰的钒酸银纳米粒子复合结构。采用简单一步水热法制备得到不同官能团功能化的石墨烯量子点，优化单层、单畴、尺寸可调的石墨烯量子点的制备方法，探索获得官能团调控对其横向尺寸、层数和可见光响应的均控制规律。此外，将石墨烯量子点与其他光催化剂进行复合，形成新型的纳米异质结光催化剂，这些纳米异质结表现出了增强的可见光响应和可见光催化降解有机污染物的能力。对纳米异质结的化学组成和微结构进行详细的表征，进而揭示微结构（尺寸、形貌、结晶状况、表面缺陷等）与可见光响应特性和光催化性能之间的关联。本项目制备的石墨烯量子点及其纳米异质结材料，有望在药物类污染物降解、劈裂水制氢、太阳能电池和超级电容器等领域获得重要应用，也为设计开发性能优异、用途广泛的多功能纳米复合材料提供理论依据。

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