LU Xiuli, HAN Yingying, LU Tongbu ＊

Institute for New Energy Materials & Low Carbon Technologies, School of Materials Science and Engineering,Tianjin University of Technology, Tianjin 300384, P. R. China.

Abstract: Graphdiyne (GDY) is a new booming carbon material with a highly π-conjugated structure that consists of sp- and sp2-hybridized carbon atoms. Due to the diverse compositions of the carbon atoms, GDYs can be divided into several forms based on their structure and periodicity. Until 2010, γ-GDY has been successfully synthesized and becomes a new member of the carbon family. Many researchers have subsequently devoted their attention to the study of GDY.Compared to the traditional carbon materials, GDY exhibits a unique carbon network and electronic structure, thereby attracting considerable attention in a variety of fields. With the development of its synthetic chemistry, many types of GDY with different structures have been synthesized and characterized. The characterization of their micromorphology is crucial for studying the synthesis procedure and understanding the properties of GDY materials. At present, the developed method can characterize GDY morphology, crystal structure, and the chemical bonds of the carbon atoms. Specifically, the morphology and thickness of GDY can be evaluated by scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. The crystal structure can be investigated using X-ray diffraction and high-resolution transmission electron microscopy. The chemical bonding of the carbon atoms can be analyzed by Raman spectroscopy, X-ray photoelectron spectroscopy, Fourier transform infrared(FT-IR) spectroscopy, C-13 nuclear magnetic resonance (13C NMR), UV-visible (UV-Vis) absorption spectroscopy, etc.However, methods for the rapid and nondestructive characterization of the highly crystalline graphdiyne are still absent,restricting the study of the intrinsic properties of GDY. Due to the unique electronic and porous structure of GDY, it has been the focus of extensive investigations in the field of catalysis. As a result of its favorable electronic structure and good capability for transferring photoexcited electrons and holes, GDY can enhance light absorption and facilitate the separation of photoexcited charge carriers in semiconductors and thereby significantly promote their photocatalytic performance. In addition, GDY can be modified using foreign elements, providing an ideal platform to prepare a highly active catalyst for the hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, etc. Furthermore,GDY can be synthesized on arbitrary substrates in a three-dimensional nanosheet array structure, which can provide a large number of channels for the transfer of electrons and a large contact area with the reactant, which is beneficial in electrocatalytic reactions. This review focused on the recent developments in characterization methods as well as the photo and electrocatalysis applications of GDY, and elaborated the opportunities and challenges for the investigation of GDY in the future.

Key Words: Carbon; Graphdiyne; Structure characterization; Photocatalytic reaction; Electrocatalytic reaction

1 引言

碳材料的发展和应用具有悠久的历史，并且一直成为科学研究的热点。众所周知，碳原子可以通过sp、sp2和sp3三种杂化形式成键，根据其不同的杂化形式以及丰富的周期性特点可以获得多种碳的同素异形体1,2。传统的碳材料包括，木炭、活性炭、天然石墨和天然金刚石等。新型碳材料包括，碳纤维、多孔碳、玻璃碳以及富勒烯、碳纳米管和石墨烯等明星碳材料。因为结构的不同，这些碳材料表现出迥异的物理化学性能。例如，sp3杂化的金刚石是自然界最硬的材料，是一种绝缘体；sp2杂化的石墨是一种非常软的材料，是良好的导电体。近年来，研究者从结构和功能多种角度对富勒烯，碳纳米管和石墨烯进行了广泛的研究，极大拓展了人们对碳材料的认识。碳材料结构和功能的多样性，使其在生物、能源、医药、催化以及电子器件等各个领域受到广泛应用3–8。长久以来，碳材料带来的惊喜促使科学家们不断寻找新的碳同素异形体，其中合成含有 sp杂化的碳材料引起广泛关注。1987年，Baughman等9通过计算，首次提出一种具有sp和sp2杂化碳原子的新型碳材料，并命名为石墨炔(Graphynes)。根据石墨炔的聚合方式以及连接苯环炔键的数量，可以组成多种不同构型的石墨单炔、石墨双炔、石墨三炔等。1997年，Haley等10理论预测了最稳定的石墨双炔的结构，即γ-石墨双炔(简称γ-GDY。注：本文中除特殊说明，GDY均指γ-GDY)。GDY具有三个独特的结构特征：1) 1,3-二炔键将苯环共轭连接形成二维平面网络结构；2) 二维平面石墨炔通过范德华力和π–π相互作用堆叠；……