不同碳氮比氮化碳(CNx)族的合成与应用

Carbon

(

IF

11.6

)

Pub Date : 2021-12-04

, DOI:

10.1016/j.carbon.2021.12.027

Chun-Yao Wang

,

Kazuhiko Maeda

,

Lee-Lee Chang

,

Kuo-Lun Tung

,

Chechia Hu

本综述重点介绍了氮化碳 (CN x ) 家族的合成和应用，不仅具有不同的碳/氮比，而且具有不同的基本单元和键合（三嗪、三唑和偶氮键）。氮化碳是一种由碳和氮组成的聚合物半导体，具有芳香族C-N环的基本sp 2 /sp 3单元。石墨氮化碳 (gC 3 N 4 )最常见的合成形式具有 2.6-2.7 eV 的带隙能量，使其适合作为可见光驱动的光催化剂。此外，2D gC 3 N 4边缘的氮原子纳米片具有孤对电子，可以在催化转化反应中充当路易斯碱位。氮化碳中的碳/氮比及其结构特征受其前体和合成过程的影响。当 gC 3 N 4 中氮含量或碳空位增加时，缺陷或未键合的氮可能作为复合中心或在禁带内引入状态，从而影响光催化反应。相反，由未键合的氮提供的额外孤对电子有利于催化反应。然而，过量的氮可能导致不稳定的 C-N-N 键的形成，从而削弱其结构稳定性。研究了 C 3 N x ( x = 3–7) 中不同单元（包括三嗪、三唑、三庚嗪和偶氮键）之间的相关性，以了解其结构特征及其在光催化和催化反应中的活性。在这篇综述中，我们总结了 CN x的最新合成方法 并讨论这些材料在能源和环境方面的应用前景。

"点击查看英文标题和摘要"

Synthesis and applications of carbon nitride (CNx) family with different carbon to nitrogen ratio

This review highlights the synthesis and applications of the carbon nitride (CNx) family with not only the different carbon/nitrogen ratios but also different basic units and linkages (triazine, triazole, and azo-linkage). Carbon nitride is a polymer semiconductor composed of carbon and nitrogen, with a basic sp2/sp3 unit of aromatic C–N rings. The most commonly synthesized form of graphitic carbon nitride (g-C3N4) has a bandgap energy of 2.6–2.7 eV, making it suitable as a visible light-driven photocatalyst. Further, nitrogen atoms at the edges of 2D g-C3N4 nanosheets have lone pair electrons, which can act as Lewis base sites in catalytic conversion reactions. The carbon/nitrogen ratio in carbon nitride and its structural features are affected by its precursors and the synthetic process. When the nitrogen content or carbon vacancy is increased in g-C3N4, the defects or unbonded nitrogen may act as recombination centers or introduce states within the forbidden gap, which affect the photocatalytic reaction. Contrastingly, the additional lone pair electrons provided by the unbonded nitrogen are advantageous to the catalytic reaction. However, excess nitrogen may result in the formation of unstable C–N–N bonds that weaken its structural stability. The correlation between different units, including triazine, triazole, tri-heptazine, and azo-linkage, in C3Nx (x = 3–7) was studied to understand its structural features and their activity in photocatalytic and catalytic reactions. In this review, we summarize the latest synthetic approaches of CNx and discuss the outlooks of these materials for energy and environmental applications.

更新日期：2021-12-15