Photocatalysis is a surface catalytic process in which photogenerated electrons are transferred to the surface of the catalyst for water reduction. In this paper, we described a novel two-step calcination strategy that not only realizes the integrating of N-doped carbon dots (NCDs) with g-C₃N₄ nanosheets, but also can the g-C₃N₄/NCDs heterojunction provide more catalytic active sites and shortens the distance of charges transport to the surface of materials. The first thermal treatment in the air lead to the formation of bulk g-C₃N₄ while NCDs was loaded in it. The subsequent secondary calcination was conducive to the exfoliation of bulk g-C₃N₄ into thinner nanosheets with thickness of 1 nm. Meanwhile, more NCDs insetted in the pristine g-C₃N₄ were exposed to the surface of materials and more catalytic active site were formed, thus promoting the hydrogen evolution. Electron paramagnetic resonance (EPR) tests certified that the g-C₃N₄ nanosheet/NCDs composites can generate more OH radical compared with bulk g-C₃N₄ and bulk g-C₃N₄/NCDs, which further validated that photogenerated electron-hole was effective separated due to more exposure of NCDs and shorter distance of electron transport to the surface. Impressively, results showed that modification of g-C₃N₄ with NCDs (1.0 wt % loading) exhibited the highest photocatalytic hydrogen production rate (3319.3 μmol g⁻¹ h⁻¹) and an apparent quantum yield of 29.8 % at 420 nm, which was 13 folds of bulk g-C₃N₄. Our work illuminates a new method for high activity g-C₃N₄/carbon dots photocatalyst in the field of photocatalysis.

光催化是一种表面催化过程，其中光生电子被转移到催化剂表面以减少水分。在本文中，我们描述了一种新颖的两步煅烧策略，该策略不仅实现了将掺杂N的碳点（NCD）与gC ₃ N ₄纳米片集成在一起，而且可以使gC ₃ N ₄ / NCD异质结提供更多的催化活性。定位并缩短电荷传输到材料表面的距离。空气中的首次热处理导致在装入NCD的同时形成块状gC ₃ N ₄。随后的二次煅烧有利于块状gC ₃ N ₄的剥落制成厚度为1 nm的更薄的纳米片。同时，更多的原始gC ₃ N ₄中嵌入的NCD暴露于材料表面，并形成了更多的催化活性位，从而促进了氢的释放。电子顺磁共振（EPR）测试证明，与块状gC ₃ N ₄和块状gC ₃ N ₄ / NCDs相比，gC ₃ N ₄纳米片/ NCDs复合物可产生更多的O H自由基，这进一步证明了光生电子空穴有效由于更多的NCD暴露和更短的电子传输到表面的距离，因此分离。令人印象深刻的是，结果表明gC的修饰具有NCD（1.0 wt％负载）的₃ N ₄表现出最高的光催化氢生成速率（3319.3μmolg ^-1 h ^-1）和在420 nm处的表观量子产率为29.8％，是整体gC ₃ N _4的13倍。。我们的工作为光催化领域的高活性gC ₃ N ₄ /碳点光催化剂提供了一种新方法。