Photocatalytic synthesis based on the oxygen reduction reaction (ORR) has shown great promise for H₂O₂ production. However, the low activity and selectivity of 2e^– ORR result in a fairly low efficiency of H₂O₂ production. Herein, we propose a strategy to enhance the proton-coupled electron transfer (PCET) process in covalent organic frameworks (COFs), thereby significantly boosting H₂O₂ photosynthesis. We demonstrated that the construction of a hydrogen-bonding network, achieved by anchoring the H₃PO₄ molecular network on COF nanochannels, can greatly improve both proton conductivity and photogenerated charge separation efficiency of COFs. Thus, COF@H₃PO₄ exhibited superior photocatalytic performance in generating H₂O₂ without sacrificial agents, with a solar-to-chemical conversion efficiency as high as 0.69%. Results indicated that a much more localized spatial distribution of energy band charge density on COF@H₃PO₄ led to efficient charge separation, and the small energy barrier of the rate-limiting step from *OOH to H₂O₂ endowed COF@H₃PO₄ with higher 2e^– ORR selectivity.

中文翻译：

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通过氢键网络在共价有机框架内进行有效的质子转移和电荷分离以促进 H2O2 光合作用

基于氧还原反应 (ORR) 的光催化合成在 H ₂ O ₂生产方面显示出巨大的前景。然而，2e ^– ORR的低活性和选择性导致H ₂ O ₂生产效率相当低。在此，我们提出了一种增强共价有机框架（COF）中质子耦合电子转移（PCET）过程的策略，从而显着促进H ₂ O ₂光合作用。我们证明，通过将H ₃ PO ₄分子网络锚定在COF纳米通道上来构建氢键网络，可以极大地提高COF的质子电导率和光生电荷分离效率。因此，COF@H ₃ PO ₄在无需牺牲剂的情况下产生H ₂ O ₂表现出优异的光催化性能，太阳能-化学转化效率高达0.69%。结果表明，COF@H ₃ PO ₄上能带电荷密度的更加局域化的空间分布导致有效的电荷分离，并且从*OOH到H ₂ O ₂的限速步骤的小能垒赋予COF@H ₃ PO ₄具有更高的2e ^– ORR选择性。