郑子祥, 王恩会, 侯新梅, 杨涛. 二维过渡金属碳化物/碳氮化物(MXene)的稳定性及改进方法[J]. 工程科学学报, 2022, 44(11): 1881-1896. DOI: 10.13374/j.issn2095-9389.2021.06.16.008
引用本文: 郑子祥, 王恩会, 侯新梅, 杨涛. 二维过渡金属碳化物/碳氮化物(MXene)的稳定性及改进方法[J]. 工程科学学报, 2022, 44(11): 1881-1896. DOI: 10.13374/j.issn2095-9389.2021.06.16.008
ZHENG Zi-xiang, WANG En-hui, HOU Xin-mei, YANG Tao. Stability and improvement of two-dimensional transition metal carbides and/or carbonitrides (MXene)[J]. Chinese Journal of Engineering, 2022, 44(11): 1881-1896. DOI: 10.13374/j.issn2095-9389.2021.06.16.008
Citation: ZHENG Zi-xiang, WANG En-hui, HOU Xin-mei, YANG Tao. Stability and improvement of two-dimensional transition metal carbides and/or carbonitrides (MXene)[J]. Chinese Journal of Engineering, 2022, 44(11): 1881-1896. DOI: 10.13374/j.issn2095-9389.2021.06.16.008

二维过渡金属碳化物/碳氮化物(MXene)的稳定性及改进方法

Stability and improvement of two-dimensional transition metal carbides and/or carbonitrides (MXene)

  • 摘要: 二维(2D)过渡金属碳化物/碳氮化物(Mxene)材料,因其良好的亲水性、导电性、柔韧性以及高赝电容等特性,在储能、海水淡化、催化、电磁干扰屏蔽、透明导电薄膜等领域有着巨大的应用潜力。然而,由于MXene材料中活性过渡金属、表面官能团以及结构缺陷的存在,使其在无保护的环境中(含有水、氧等)很容易被氧化,导致稳定性较差。MXene材料的氧化破坏了其片状结构,降低了其电导率,限制了其更广泛的应用。本文简要介绍了MXene的结构和合成方法;综述了MXene在不同条件下不稳定的机理,即表面官能团和周围介质发生氧化反应;并从储存条件、合成方法、气氛热处理、表面电性修饰、掺杂等方面讨论了提高MXene稳定性的方法。

     

    Abstract: In recent years, a new family of two-dimensional (2D) transition metal carbides and/or carbonitrides, labeled MXenes, has attracted immense attention from researchers. Due to unusual hydrophilicity, electrical conductivity, flexibility, and pseudocapacitance, MXenes have great potential application in energy storage, water desalination, catalysis, electromagnetic interference shielding, transparent conductive films, and so on. However, MXenes exhibit poor stability because of their structural defects, active transition metals, and termination groups. These greatly destroy the sheet structure and decrease their conductivity, thereby restricting their application fields. In this review, the structure and synthesis methods of MXenes are briefly introduced. Then, we focus on current research studies regarding the stability of MXenes. The mechanism of oxidation is also discussed. Ti vacancies and the edges are the preferential oxidation sites in MXene sheets. Based on this, the methods to improve the MXene stability, including controlling the storage environment, improving the synthesis method, annealing in an atmosphere, modification based on the surface electric state, and doping impurities, are further discussed. First, the optimal requirements for MXenes storage are low temperature, desiccation, and oxygen isolation. Second, soft etching methods must be applied to synthesize MXenes to reduce the defect density of their sheet surface. Then, annealing MXenes in an atmosphere can enable the tailoring of the surface structure and functional groups for enhanced MXene stability. Lastly, more methods have been applied to improve the stability of MXenes based on their surface electric state. Since the MXene sheet surface is electronegative, their oxidation can be impeded by loading cations into the sheets. Similarly, since the edge of these sheets is electropositive, polyanions can be absorbed onto the edge to protect the MXene sheets. Moreover, compositing metal oxides, organic macromolecules, and nanocarbon on their surface can also improve the stability of MXenes. Finally, doping with impurities can also improve the band energy of MXenes. Meanwhile, our idea to improve the stability of MXenes is also briefly introduced.

     

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