石墨相氮化碳基纳米异质结光电化学传感平台的构筑及在食品安全检测中的应用研究

Developing novel photoelectrochemical materials with high-performance is the precondition and guarantee for the fabrication of photoelectrochemical sensing platform with high sensitivity and high stability. Nano heterojunction can effectively control the band structure, broaden the scope of light absorption, improve the photostability, promote the effective separation of electrons and holes, suppress the recombination of photo-induced carriers, and significantly improve the quantum efficiency, so as to break through the bottlenecks of single photoactive materials in the field of photoelectrochemical sensing. Motivated by these advantages above, the aim of this project is to use graphitic carbon nitride (g-C3N4) with unique energy band structures and excellent chemical stability as two dimensional supporting materials, coupling with different single component material possessing useful physical and chemical properties, adopt a variety of methods to prepare a series of g-C3N4 nano heterojunctions. Then g-C3N4 based heterojunction with high-performances, high conversion efficiency and high photoelectrochemical stability will be selected to fabricate photoelectrochemical sensing platform. Furthermore, by combining the biological recognition elements, the recognition mechanism of the direct/indirect interaction between photoactive materials and dangerous components in food will be clarified, and the photocurrent signal changes before and after the biological recognition will be explored to develop photoelectrochemical sensing technology in the field of food safety. The implementation of this project is of significant academic and practical value for the design, preparation and application of g-C3N4 based heterojunction in food analysis field.

发展新型高性能光电活性材料是构筑高灵敏度、高稳定性光电化学传感平台的前提和保证。新型高效纳米异质结可以有效调控其能带结构，促进光生电子和空穴的有效分离，抑制光生载流子的复合，显著提高量子效率，从而克服单一光电活性材料在光电化学传感领域应用中存在的瓶颈。本项目以石墨相氮化碳（g-C3N4）为功能载体，耦合各种单一材料有益的物理化学性能，采用多种纳米制备技术，调控合成一系列g-C3N4基纳米异质结；从中筛选出光电性能优异、光电转换效率高、光电化学稳定的g-C3N4基纳米异质结，用于构建光电化学传感平台；在此基础上结合生物识别元件，进一步阐明食品有毒有害物质与光电活性材料之间的直接/间接相互作用机制，揭示生物识别过程前后光电流信号变化的机理，发展食品安全领域中新型光电化学传感检测技术。因此本项目的实施，对丰富和发展g-C3N4基纳米异质结的设计制备及其在食品分析领域的应用具有重要的理论与应用。

食品安全关系国计民生，因此发展简便、快速、准确、高效的检测方法具有重要意义。本项目以具有独特半导体能带结构和优异化学稳定性的石墨相氮化碳（g-C3N4）为功能载体，采用多种合成技术，调控制备了一系列光电化学活性良好的二元或三元g-C3N4基纳米异质结，解决了单体光电化学活性材料电子转移速率慢、电子-空穴对重组快等问题。通过筛选可见光响应范围宽、光电转换效率高和信号输出稳定的g-C3N4基功能纳米异质结作为电极修饰材料，构建了一系列光电化学传感平台。通过考察异质结构种类、异质结间比例、组成、形态分布等因素与光电性能的关系，揭示了复合物光电化学性能增强机制及信号放大机理；通过探究生物识别过程对输出信号变化的传感机理，阐明了食品中有毒有害物质与光电活性材料和生物识别元件之间的相互作用规律。项目的实施完成，拓展了g-C3N4基纳米异质结材料在分析检测领域的应用，为发展食品安全领域中新型光电化学传感检测技术提供了理论和实践依据。