无支撑柔性夹心型石墨烯复合纸电极的构筑及其电化学传感研究

The development of new types of modified electrodes has triggered significant research efforts due to the rising progress of modern electrochemical sensor. We propose the design of a novel free-standing flexible electrode based on graphene nanohybrid paper and explore its use for electrochemical sensing of biomarker hydrogen peroxide: The ordered sandwich-structured nano- electrocatalysts/ionic liquid/graphene hybrid paper will be fabricated by functionalizing graphene nanosheets with ionic liquids to form macroscopic paper-like structure, which will enhance the solution processability and film-forming ability of graphene materials; And then modifying the graphene paper with nano-electrocatalysts via ultrasonic-electrodeposition and interfacial self-assembly methods to improve its nonenzymatic catalytic activity and electrochemical sensing performance toward hydrogen peroxide. The modular nature of this approach for designing flexible working electrode of electrochemical sensor in the framework of "function orientation-structure tuning-performance optimization" opens new possibilities to systematically study the formation mechanism, interaction and structure-properties relationship of different component in the graphene nanocomposite. We envision that this proposal will provide new insights on the fabrication of flexible paper electrodes for a diverse range of applications, which is of important significance for designing advanced light-weight and flexible electrochemical sensor, and will contribute to the development of modern electronic devices.

新型电化学传感器的快速发展推动各种新式修饰电极不断涌现。本课题提出以石墨烯复合纸作为无支撑柔性电极，以生物标志物过氧化氢为分析目标，构建电化学传感平台的全新思路：拟开发分子水平上石墨烯纳米片层表面修饰方法，通过离子液体对石墨烯修饰提高石墨烯材料的可溶液操作性和成膜性；以修饰化石墨烯纳米片层为结构单元组装无支撑石墨烯纸宏观结构；发展纳米尺度下石墨烯纸与其它功能材料复合的绿色可控制备技术，采用超声电沉积法和界面自组装法将纳米电催化材料负载到石墨烯薄膜上，构筑高级有序夹心型纳米电催化剂/离子液体/石墨烯复合纸。设计"功能导向-结构调控-性能优化"研究体系，阐明复合材料各层次组分的形成机制、相互作用和构效关系，通过各组分间的协同效应提高石墨烯复合纸电极对过氧化氢的无酶催化和电化学传感性能，制备具有普适意义的高性能纸质电极，为构建轻质柔性电化学传感器提供创新的方法，为研发新型柔性器件奠定坚实的基础。

新型电化学传感器的快速发展推动各种新式修饰电极不断涌现。本课题以夹心型石墨烯复合纸作为无支撑柔性电极构建了用于检测多种目标分析物的高性能电化学传感平台：课题研发了石墨烯纳米片层表面修饰方法，合成了1-丁基-3-甲基咪唑四氟硼酸盐等不同种类的离子液体，通过离子液体与石墨烯之间的阳离子-π键相互作用将离子液体分子修饰到石墨烯表面，提高了石墨烯材料的可溶液操作性和成膜性；开发了石墨烯纸规模化制备工艺，采用真空抽滤法、溶液铸造法和印刷法，以修饰化的石墨烯纳米材料作为结构单元，组装无支撑石墨烯纸宏观结构；发展了石墨烯与功能纳米材料复合的绿色可控制备技术，应用多种高效方法如低温化学还原、电沉积/聚合、水热沉淀法、涂敷法等将功能纳米纳米材料如铂金合金、金纳米花、铂钴合金纳米粒子、聚苯胺纳米管、二氧化锰纳米线、镍钴氢氧化物纳米片、多孔纳米金薄膜等负载到石墨烯薄膜上，制备了不同结构和组成的夹心型墨烯复合纸。该夹心型复合纸电极结合了负载石墨烯纸上的功能纳米材料独特的电催化性能和石墨烯纸基体导电性和稳定性好、机械强度高的优点；以夹心型石墨烯复合纸作为柔性电极构建的高性能电化学传感器灵敏度高、选择性、重现性和稳定性好，实现了对于多种目标分析物如过氧化氢、葡萄糖、重金属离子、多巴胺等快速、准确、超灵敏检测，其中过氧化氢的检出限低至20 nM。多巴胺的检出限低至2 nM，重金属离子Cd2+和Pd2+检出限低至分别为0.2 nM和0.1 nM，在实际应用中，采用自制的传感器检测血糖浓度与医院结果一致，检测东湖水样和自来水样中重金属含量相对标准偏差小于5%。因此，本项目的开展为研发具有普适意义的柔性纸质电极和高性能电化学传感体系提供创新方法，在环境和生物医学领域具有广泛的应用前景。