Ultrathin g-C₃N₄ nanosheets have been fabricated via a two-step calcination regulated by melamine precursors at a high heating rate (30 °C min⁻¹). The resulting g-C₃N₄ nanosheets were further employed as carriers for the growth of carbon quantum dots (CQDs) and (110) exposed α-Fe₂O₃ through the PVP-enabled adsorption effects by a solvothermal process. It was discovered that the so fabricated ternary photocatalyst α-Fe₂O₃/CQD@g-C₃N₄ presented a broad-spectrum absorption range (up to 800 nm) and particularly enhanced active sites of photogenerated electrons for highly efficient photocatalytic oxygen reduction toward H₂O₂ evolution in pure water. A H₂O₂ production rate of 1.16 μM min⁻¹ could be expected for the developed photocatalyst under visible light irradiation, which is about 19 times faster than that of pure ultrathin g-C₃N₄. Herein, the loaded Fe₂O₃ could transform the H₂O₂ evolution from two-step single-electron reduction into one-step two-electron one, as verified by the various active species experiments and rotating ring-disk electrode tests. This work presents a new perspective in designing ultrathin g-C₃N₄ through a simple method of precursor-regulated calcination, which features more outstanding advantages than the conventional exfoliation of bulk g-C₃N₄ towards ultrathin g-C₃N₄. More importantly, it provides an optimized photocatalytic reaction route of two-electron oxygen reduction for efficient H₂O₂ production in pure water under visible light irradiation, without the need for noble metals or organic sacrificial agents.

中文翻译：

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使用具有广谱响应的三元α-Fe2O3/ CQD @ g-C3N4光催化剂通过两电子氧还原反应生成无牺牲剂的光催化H2O2

已经通过三步煅烧由三聚氰胺前体调节的两步煅烧以高加热速率（30°C min ^-1）制备了超薄gC ₃ N ₄纳米片。将得到的GC ₃ Ñ ₄纳米片进一步用作载体为碳量子点（CQDs）和生长（110）暴露的α-Fe ₂ ö ₃通过溶剂热方法启用PVP-吸附效果。据发现，在这样制造的光催化剂的三元的α-Fe ₂ ö ₃ / CQD @ GC ₃ Ñ ₄他提出了一个广谱吸收范围（高达800 nm），特别是增强了光生电子的活性位，以实现高效的光催化氧还原，使其在纯水中向H ₂ O ₂析出。在可见光照射下，已开发的光催化剂的AH ₂ O ₂生产率有望达到1.16μMmin ^-1，比纯超薄gC ₃ N ₄快约19倍。在此，负载的Fe ₂ O ₃可以转化H ₂ O ₂从两步单电子还原到一步两电子还原的过程，已通过各种活性物种实验和旋转环盘电极测试得到验证。这项工作提出了一种通过前体调节煅烧的简单方法设计超薄gC ₃ N ₄的新视角，与传统的将大块gC ₃ N ₄剥落至超薄gC ₃ N ₄的常规方法相比，它具有更为突出的优势。更重要的是，它为高效H ₂ O ₂提供了优化的两电子氧还原的光催化反应路线 在可见光辐射下在纯水中生产，不需要贵金属或有机牺牲剂。