多孔石墨烯微观结构的电子转移效应及其电化学性能的研究

Due to the depletion of fossil fuels and increasing environmental pollution and food safety concerns, graphene becomes one of the most attractive materials for the electrochemical analysis, energy conversion and storage. However, two-dimensional sheets such as graphene tend to aggregate and restack during the electrode fabrication process, leading to the reduction of the real surface area, the difficult access of electrolytes/ions, and the limitation of the electron transfer. To address this issue, two-dimensional holey graphene (H-G) which can be beneficial to the easy access of electrolytes and rapid diffusion of ions due to the presence of holes in the graphene basal plane would be studied as electrode material. The defect density and edge ratio could be changed and increased by turning the pore size and functional groups on the surface of H-G, and changing the H-G orientation form random stacking to vertical. Then, in order to analyze the relationship of the electron transfer with defect density and boundary effect of H-G, the effect of microstructure including basal plane microstructure (hole size and functional group), dimensional microstructure(random stacking orientation and vertical orientation) on the electron transfer would be investigated. It is significant to clarify the H-G electron transfer mechanism. The research results will provide a theoretical and experimental basis for graphene based electrode materials application and pave the way towards the development of feasible strategies for tailoring the porosity of two-dimensional nanostructures for advanced electrochemical sensor and energy storage devices.

面对石化资源短缺，环境污染和食品安全问题突出，石墨烯基材料在能量存储与转换、电化学分析等方面展示出重要应用。但是石墨烯易团聚，导致电极的有效面积锐减，离子/电解质等扩散能力降低，电子传递能力减弱等。本项目将采用多孔石墨烯（H-G）作为电极材料，其基面孔洞结构能促进传质能力提升，从而使得电子传递能力成为制约电化学性能的关键要素。通过对基面微结构（孔径尺寸、官能团）和空间微结构（垂直取向、平铺取向）的调控，实现H-G的缺陷密度和边界比例的改变与提高，进而探索H-G的微观结构对电子传递能力的影响，揭示缺陷密度、边界效应对H-G的电子转移的作用规律，对阐明H-G的电子转移机制具有重要意义。通过促进电子转移能力的提高，提升电化学性能，对石墨烯基电极材料的实际应用具有重要的理论指导作用，并且为设计开发更为有效的纳米二维孔洞材料传感器、能量存储/转换器提供方向。

石墨烯作为性能优异的二维材料在电化学分析方面展示出重要应用。但是石墨烯易团聚，导致电极的有效面积锐减，离子/电解质等扩散能力降低，电子传递能力减弱等。本项目通过光芬顿-电化学法和水热法等方法制备了二维基面孔洞结构的多孔氧化石墨烯（HGO），多孔石墨烯（H-G）， 三维多孔石墨烯（3D-HG）和三维N掺杂多孔石墨烯(N-HG)，实现了H-G基面孔径尺寸、异种原子掺杂种类，以及空间取向的调控。通过提高H-G的缺陷密度和边界比例，改善了H-G电极的电化学性能，揭示缺陷密度、边界效应对H-G的电子转移的作用规律，并设计开发了以H-G为修饰材料的多种电化学传感器。