Graphitic carbon nitride (g‐CN) is one potential metal‐free photocatalyst. The photocatalytic mechanism of g‐CN is related to the heptazine ring building unit. Melem is the simplest heptazine‐based compound and g‐CN is its polymeric product. Thus, studies on the photophysical properties of melem will help to understand the photocatalytic mechanism of heptazine‐based materials. Herein, the spectroscopic features of melem were systematically explored through measuring its absorption spectrum, fluorescence spectrum, and fluorescence decay. Both fluorescence spectroscopy and fluorescence decay measurements show that the condensation of melamine to melem causes stronger photoluminescence, whereas the condensation of melem to g‐CN causes weaker photoluminescence. In addition, all observations reveal that a mixture of monomer melem and its higher condensates is more easily obtained during the preparation of melem, and that the higher condensates of melem affect the photophysical properties of melem dominantly. The photocatalytic hydrogen evolution of melem has also been measured and the monomer melem has negligible photoinduced water‐splitting activity.

中文翻译：

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蜜em的光物理和光催化：光谱再研究

石墨氮化碳（g-CN）是一种潜在的无金属光催化剂。g-CN的光催化机理与庚嗪环的构建单元有关。Melem是最简单的基于庚嗪的化合物，而g-CN是其聚合产物。因此，对榄香烯的光物理性质的研究将有助于了解庚嗪基材料的光催化机理。在此，通过测量其吸收光谱，荧光光谱和荧光衰减来系统地探索梅莱姆的光谱特征。荧光光谱法和荧光衰减测量法均表明，三聚氰胺与蜜胺的缩合引起更强的光致发光，而蜜胺与g-CN的缩合引起较弱的光致发光。此外，所有观察结果表明，在制备榄香烯时，更容易获得单体榄香素及其较高缩合物的混合物，而榄香烯的较高缩合物主要影响榄香烯的光物理性质。也已经测量了melem的光催化氢逸出，并且单体melem具有可忽略的光致水分解活性。