Self-assembled synthesis of defect-engineered graphitic carbon nitride nanotubes for efficient conversion of solar energy
Self-assembled synthesis of defect-engineered graphitic carbon nitride nanotubes for efficient conversion of solar energy
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自组装合成缺陷工程石墨氮化碳纳米管用于高效太阳能转换
DOI：
10.1016/j.apcatb.2017.11.041
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发表时间：
2018-06-05
影响因子：
22.1
通讯作者：
Li, Huaming
中科院分区：
文献类型：
--
作者：
Mo, Zhao;Xu, Hui;Li, Huaming
采用单一的三聚氰胺前驱体，通过无酸碱、无绿色合成方法，首次合成了高产率、尺寸均匀、氮缺陷丰富的石墨碳氮纳米管（g-C3 N4 nanotubes）。该方法利用部分三聚氰胺缓慢原位转化为氰尿酸，随后与其余三聚氰胺分子自组装形成超分子中间体。下面的热解将超分子中间体转化为具有丰富的氮缺陷的g-C3 N4纳米管。这种形貌比传统的以三聚氰胺和三聚氰酸的混合物为前驱体的分子自组装具有更好的性能。长径比为30-70的有序管状形态的g-C3 N4纳米管具有优异的析氢速率（118.5 μ molh（-1）），明显上级体相g-C3 N4。在420 nm的光照射下，g-C3 N4纳米管的表观量子效率达到6.8%，这在一维g-C3 N4纳米管、纳米线和纳米棒中名列前茅。光催化性能的改善得益于管状结构和氮缺陷，这导致了改善的光吸收，更多暴露的活性边缘，氮缺陷活性位点，增强的电荷转移和分离效率，更高的表面积，快速和长距离的电子传输，以及更长的荧光寿命。除析氢反应外，g-C3 N4纳米管在环境治理和有机染料的光电化学检测方面也有着广泛的应用。
High-yield and uniform-size graphitic carbon nitride nanotubes (g-C3N4 nanotubes) with abundant nitrogen defects are synthesized for the first time by a green and acid-alkali-free synthesis using a sole melamine precursor. This approach utilizes the slow in-situ conversion of part of melamine into cyanuric acid and consequent molecular self-assembly with the rest of melamine to form supramolecular intermediate. The following pyrolysis converts the supramolecular intermediate to g-C3N4 nanotubes with abundant nitrogen defects. The morphology thus resulted preferable performance than the traditional molecular self-assembly in which the mixture of melamine and cyanuric acid is used as precursors. The g-C3N4 nanotubes with orderly tubular morphology of length-diameter ratio of 30-70 exhibit excellent hydrogen evolution rate (118.5 mu mol h(-1)), which is obviously superior to the bulk g-C3N4. The apparent quantum efficiency of g-C3N4 nanotubes under irradiation at 420 nm is achieved at 6.8%, which is among the top of one dimensional (1D) g-C3N4 structure, such as g-C3N4 nanotubes, nanowires and nanorods. The improved photocatalytic performance benefits from the tubular structure and the nitrogen defects, which lead to the improved optical absorption, more exposed active edges, nitrogen defects active sites, enhanced charge transfer and separation efficiency, higher surface area, fast and long-distance electron transport, and longer fluorescence lifetime. Beside hydrogen evolution reaction, the g-C3N4 nanotubes also have broad applications in environmental treatment and photoelectrochemical detection of organic dyes.