A precursor‐engineering strategy coupled with a microwave molten‐salt process (PE‐MWMS) is developed to synthesize graphitic carbon nitride (g‐C₃N₄) with an isotype triazine/heptazine‐based g‐C₃N₄ heterojunction as a photocatalyst for the hydrogen evolution reaction (HER) under visible light illumination. Four hybrid precursor combinations—thiourea/melamine, thiourea/dicyandiamide, urea/melamine, and urea/dicyandiamide—are used to synthesize g‐C₃N₄ heterojunctions by the PE‐MWMS process. Control experiments indicate that the precursor components and microwave treatment have a great effect on the HER performance of the g‐C₃N₄ samples. Samples synthesized with the optimal molar ratios of thiourea/melamine (2:1), thiourea/dicyandiamide (2:1), urea/melamine (3:1), and urea/dicyandiamide (3:1), exhibit the highest HER rates of 3135, 2519, 2844, and 2565 μmol g⁻¹ h⁻¹, respectively. The amounts of heptazine and triazine units in the g‐C₃N₄ samples can be easily adjusted by changing the ratios of the hybrid precursors and play a decisive role in improving the photocatalytic HER activity. Because of the unique composition and microstructure, the efficient separation of electron–hole pairs, the broadened photo‐absorption edges, and the narrowed band gaps, the as‐obtained triazine/heptazine‐based g‐C₃N₄ nanostructures exhibit promising activity for HER application.

中文翻译：

---

前体工程耦合微波熔盐策略增强了g-C3N4纳米结构的光催化氢逸出性能

开发了一种前体工程设计策略以及微波熔融盐工艺（PE-MWMS），以基于三嗪/庚嗪的同种型g-C ₃ N ₄异质结作为碳纳米管来合成石墨碳氮化物（g-C ₃ N ₄）。可见光照射下用于析氢反应（HER）的光催化剂。四种杂化前体组合-硫脲/三聚氰胺，硫脲/双氰胺，尿素/三聚氰胺和尿素/双氰胺-通过PE-MWMS工艺合成g-C ₃ N ₄异质结。对照实验表明，前体组分和微波处理对g‐C ₃ N ₄的HER性能有很大影响。样品。以硫脲/三聚氰胺（2：1），硫脲/双氰胺（2：1），尿素/三聚氰胺（3：1）和尿素/双氰胺（3：1）的最佳摩尔比合成的样品显示出最高的HER率分别为3135、2519、2844和2565μmolg ^-1  h ^-1。通过更改杂化前体的比例，可以轻松调节g‐C ₃ N ₄样品中庚嗪和三嗪单元的数量，并在提高光催化HER活性方面起决定性作用。由于独特的组成和微观结构，有效的电子-空穴对分离，更宽的光吸收边缘和更窄的带隙，因此获得了基于三嗪/庚嗪的g-C ₃ N ₄ 纳米结构表现出对HER应用的有希望的活性。