Controllable Synthesis of Two-Dimensional Graphdiyne Films Catalyzed by a Copper(II) Trichloro Complex

Graphdiyne (GDY) is a carbon allotrope with an alkyne-rich framework constructed from the coupling of terminal alkynes in hexaethynylbenzene (HEB); thus, efficient acetylene–acetylene bond coupling is essential to synthesize high-quality GDY. In this work, a copper(II) trichloro catalyst (CuTC) was introduced for GDY growth in the presence of a Cu foil, N,N,N,N′-tetramethylethylenediamine (TMEDA), and trichloromethane (CHCl3) at a mild temperature. High-quality GDY sheets on a gram scale can be obtained at a yield of 42% by increasing the content of HEB and Cu foil, which forms the foundation for their further applications. A mechanistic study demonstrated that Cu–Cl bonds play an important role in the formation of the Cu(II)–diacetylide intermediate, which extended GDY growth to other benign solvents, such as dichloromethane (DCM), ethyl acetate (EA), tetrahydrofuran (THF), and N,N-dimethylformamide (DMF). Besides, GDY analogues H-GDY, COOCH3-GDY, and Py-GDY can be successfully grown on the surface of a Cu foil with a higher 1,3-diyne content than that mentioned in previous reports. GDY synthesized by the present method showed enhanced photocatalytic activity in hydrogen evolution upon hybridization with π-conjugated molecules through a π–π stacking interaction, which is powerful for constructing novel heterojunction materials by adjusting the electronic structure of GDY, thereby enhancing the light absorption ability of the system. Our work will contribute to the preparation of high-quality GDY and its analogues and extend their applications in various areas in the future.