Rational synthesis of ultrathin graphitic carbon nitride nanosheets for efficient photocatalytic hydrogen evolution
Rational synthesis of ultrathin graphitic carbon nitride nanosheets for efficient photocatalytic hydrogen evolution
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DOI：
10.1016/j.carbon.2017.06.020
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发表时间：
2017-09-01
期刊：
影响因子：
10.9
通讯作者：
Shi, Weidong
中科院分区：
文献类型：
--
作者：
Hong, Yuanzhi;Li, Changsheng;Shi, Weidong
具有独特结构和电子特性的石墨氮化碳（g-C3N4）纳米片在光催化领域受到广泛关注，但超薄g-C3N4的直接合成仍然是一个巨大的挑战。在此，首先以水热预处理的三聚氰胺为前驱体，通过直接热煅烧制备了高性能的g-C3N4纳米片。采用多种技术来表征所制备的样品。结果表明，合成样品的形貌、微观结构和物理化学性质很大程度上取决于水热温度。通过优化的 200 摄氏度水热预处理可以合成厚度约为 3 nm 的所需 g-C3N4 纳米片。与块状g-C3N4相比，超薄g-C3N4纳米片具有高比表面积、大电子能带结构和快速光致电子空穴分离能力。结果，所得纳米片表现出优异的可见光驱动光催化水分解析氢性能（503 mmol h(-1) g(-1)），比本体粉末高6倍以上。这项工作突出了一种可行但简单的生产超薄类石墨纳米片的策略，并开发了一种用于能量转换的高效无金属纳米材料。 (C) 2017 年由爱思唯尔有限公司出版。
Graphitic carbon nitride (g-C3N4) nanosheets with unique structural and electronic properties have received much attention in photocatalysis, yet the direct synthesis of ultrathin g-C3N4 is still a big challenge. Herein, high-performance g-C3N4 nanosheets were firstly prepared by directly thermal calcination of the hydrothermally pretreated melamine as precursor. Multiple techniques were carried out to characterize the as-prepared samples. Results shown that the morphologies, microstructures, and physicochemical properties of as-synthesized samples are strongly depended on the hydrothermal temperature. The desired g-C3N4 nanosheets with a thickness of around 3 nm could be synthesized through an optimized 200 degrees C hydrothermal pretreatment. Compared to the bulk g-C3N4, the ultrathin g-C3N4 nanosheets possessed high specific surface area, large electronic band structure, and fast photoinduced electron-hole separation capability. As a consequence, the resultant nanosheets exhibited excellent visible-light-driven photocatalytic water splitting performance for hydrogen evolution (503 mmol h(-1) g(-1)), which is over 6 times higher than the bulk powder. This work highlights a feasible but simple strategy for the production of ultrathin graphite-like nanosheets and develops an efficient metal-free nanomaterial for application in energy conversion. (C) 2017 Published by Elsevier Ltd.