Turning Defects Into Advantages: Structures, Synthesis, and Applications of 2D Amorphous Carbon

Abstract 2D amorphous carbon (2DAC) has attracted significant interest due to its tunable structural defects, which can be strategically engineered to achieve superior control over physical properties compared to its crystalline counterparts. The unique combination of diverse carbon bonding configurations—single, double, and triple bonds—integrated with the inherent advantages of an amorphous 2D framework enables the precise design of 2DACs with tailored functionalities, positioning it as a promising platform for applications in electronics, energy conversion, and catalysis. Notably, rather than being a limitation, the defects within 2DAC introduce localized electronic states and active sites, enhancing its functional versatility. This review provides a comprehensive overview of 2DAC, covering its structure, synthesis, properties, and potential applications. It begins by outlining the development of 2DAC, with a particular focus on structural controversies. Subsequently, its preparation strategies and growth mechanisms are systematically summarized. In the following, distinctive mechanical, electrical, and membrane properties of 2DAC are fully examined, meanwhile its potential as a buffer layer in electronic devices is highlighted. Finally, key challenges and future research directions, exploring prospects for the design and properties of amorphous materials and providing insights that may shape the future of advanced materials science, are discussed.