The photosynthesis of hydrogen peroxide (H₂O₂) from pure water and oxygen using metal-free photocatalysts offers a renewable approach to convert solar energy to storable chemical energy. However, the efficiency of H₂O₂ photosynthesis is often hindered by the rapid recombination of photogenerated charge carriers. Herein, we present an elegantly designed covalent triazine framework (CTF) photocatalyst, denoted as Ace-asy-CTF, with a stepwise electron transfer pathway for the highly efficient photosynthesis of H₂O₂. Notably, Ace-asy-CTF possesses localized excited-state charge distribution and stepwise electron transfer that is created by the weakly conjugated acetenyl units in the asymmetric frameworks, as revealed by transient spectroscopies and further supported by theoretical calculations. Meanwhile, the introduced acetenyl units also serve as active sites for the oxygen reduction reaction (ORR). The simultaneously enhanced stepwise charge transfer and two-step 2e^– ORR in Ace-asy-CTF result in an excellent H₂O₂ yield of 2594 μmol g^–1 h^–1, directly produced from oxygen and pure water without requiring any sacrificial reagents. This work paves the way for the development of next-generation metal-free catalysts, providing a feasible benchmark for the highly efficient and stable photosynthesis of H₂O₂.

中文翻译：

---

通过具有逐步电子转移的共价三嗪框架增强光催化生产过氧化氢


使用无金属光催化剂从纯水和氧气中光合作用过氧化氢 （H₂O₂） 提供了一种将太阳能转化为可储存化学能的可再生方法。然而，H₂O₂ 光合作用的效率经常受到光生载流子快速复合的阻碍。在此，我们提出了一种设计优雅的共价三嗪框架 （CTF） 光催化剂，表示为 Ace-asy-CTF，具有用于 H₂O₂ 高效光合作用的逐步电子转移途径。值得注意的是，Ace-asy-CTF 具有局部激发态电荷分布和逐步电子转移，这是由不对称框架中的弱共轭乙酰基单元产生的，瞬态光谱学揭示了这一点，并进一步得到了理论计算的支持。同时，引入的乙酰基单元也用作氧还原反应 （ORR） 的活性位点。在 Ace-asy-CTF 中同时增强的逐步电荷转移和两步 2e^– ORR 可直接由氧气和纯水产生 2594 μmol g^–1 h^–1 的出色 H₂O₂ 产率，无需任何牺牲试剂。这项工作为下一代无金属催化剂的开发铺平了道路，为 H₂O₂ 的高效稳定光合作用提供了可行的基准。