Graphitic carbon nitride (g-C₃N₄), a metal-free semiconductor with a band gap of 2.7 eV, has received considerable attention owing to its fascinating photocatalytic performances under visible-light. g-C₃N₄ exhibits high thermal and chemical stability and non-toxicity such that it has been considered as the most promising photocatalyst for environmental improvement and energy conservation. Hence, it is of great importance to obtain high-quality g-C₃N₄ and gain a clear understanding of its optical properties. Herein, we report a high-yield synthesis of g-C₃N₄ products via heating of high vacuum-sealed melamine powder in an ampoule at temperatures between 450 and 650 °C. Using transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), electron energy loss spectroscopy (EELS), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), the chemical composition and crystallization of the as-produced g-C₃N₄ are demonstrated. A systematic optical study of g-C₃N₄ is carried out with several approaches. The optical phonon behavior of g-C₃N₄ is revealed by infrared and Raman spectroscopy, and the emission properties of g-C₃N₄ are investigated using photoluminescence (PL) spectroscopy, while the photocatalytic properties are explored by the photodegradation experiment.

中文翻译：

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gC ₃ N ₄ †的高产率合成和光学性质

石墨化氮化碳（gC ₃ N ₄）是一种带隙为2.7 eV的无金属半导体，由于其在可见光下的引人入胜的光催化性能而备受关注。gC ₃ N ₄表现出高的热稳定性和化学稳定性以及无毒性，因此被认为是改善环境和节约能源的最有希望的光催化剂。因此，获得高质量的gC ₃ N ₄并清楚了解其光学性质非常重要。此，我们报告的GC高产合成₃ Ñ _4级的产品通过在安瓿中将高真空密封的三聚氰胺粉末在450至650°C的温度下加热。使用透射电子显微镜（TEM），扫描透射电子显微镜（STEM），电子能量损失光谱（EELS），热重分析（TGA），X射线衍射（XRD）和X射线光电子能谱（XPS）对所生成的gC ₃ N _4的组成和结晶进行了说明。用几种方法对gC ₃ N ₄进行了系统的光学研究。gC ₃ N ₄的光学声子行为通过红外和拉曼光谱揭示，并且gC ₃ N ₄的发射特性 使用光致发光（PL）光谱进行了研究，同时通过光降解实验探索了光催化性能。