Bridging-nitrogen defects modified graphitic carbon nitride nanosheet for boosted photocatalytic hydrogen production
Bridging-nitrogen defects modified graphitic carbon nitride nanosheet for boosted photocatalytic hydrogen production
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DOI：
10.1016/j.ijhydene.2021.05.197
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发表时间：
2021-07-21
影响因子：
7.2
通讯作者：
Tang, Junwang
中科院分区：
文献类型：
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作者：
Luo, Lei;Wang, Keran;Tang, Junwang
增强可见光吸收和电荷分离是提高石墨碳氮化物光催化性能的关键。本文以三聚氰胺和六亚甲基四胺为前驱体，通过固相共聚和热处理制备了多孔氮缺陷桥联石墨氮化碳纳米片。通过全面的表征证明了嵌入薄层框架中的大量孔隙和桥接氮缺陷。合成的织构和电子结构使得光催化产氢的显著改善成为可能，其中D-CNNS（0.3）的优化样品在可见光照射（l > 420 nm）下表示2497.1 mmol中心点g（-1）中心点h（-1）的析氢速率。与原始纳米片和块状氮化碳相比，这分别是约10.4和41.1倍的改进。理论和实验结果都表明，氮桥缺陷有利于增强光吸收，促进电荷分离和转移。与扩大的表面积一起，优化的纳米片样品在可见光区显示出显着提高的量子产率。(C)2021年氢能出版有限责任公司。由Elsevier Ltd.出版。保留所有权利。
Reinforcing the visible photon absorption and charge separation are the key issues to maximize the photocatalytic performance of graphitic carbon nitride. Herein, holey bridging-nitrogen-defected graphitic carbon nitride nanosheets were prepared through solid-state copolymerization and subsequently thermal annealing with melamine and hexamethylenetetramine as the precursors. Numerous pores and bridging nitrogen defects that embedded into the thin-layer framework were evidenced through comprehensive characterization. The synthesized textural and electronic structure enables the significant improvement of photocatalytic hydrogen production, with the optimized sample of D-CNNS(0.3) representing a hydrogen evolution rate of 2497.1 mmol center dot g(-1)center dot h(-1) under visible light irradiation (l > 420 nm). This is about 10.4 and 41.1 folds improvement compared with pristine nanosheets and bulk carbon nitride, respectively. Both experimental and theo-retical results demonstrate the bridging nitrogen defects are beneficial to enhance pho-toabsorption, promote charge separation and transfer. Together with the enlarged surface area, the optimized nanosheet sample shows a dramatically improved quantum yield in visible region. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.