In photocatalysis, reducing the exciton binding energy and boosting the conversion of excitons into free charge carriers are vital to enhance photocatalytic activity. This work presents a facile strategy of engineering Pt single atoms on a 2D hydrazone-based covalent organic framework (TCOF) to promote H₂ production coupled with selective oxidation of benzylamine. The optimised TCOF-Pt SA photocatalyst with 3 wt% Pt single atom exhibited superior performance to TCOF and TCOF-supported Pt nanoparticle catalysts. The production rates of H₂ and N-benzylidenebenzylamine over TCOF-Pt SA3 are 12.6 and 10.9 times higher than those over TCOF, respectively. Empirical characterisation and theoretical simulation showed that the atomically dispersed Pt is stabilised on the TCOF support through the coordinated N₁-Pt-C₂ sites, thereby induing the local polarization and improving the dielectric constant to reach the low exciton binding energy. These phenomena led to the promotion of exciton dissociation into electrons and holes and the acceleration of the separation and transport of photoexcited charge carriers from bulk to the surface. This work provides new insights into the regulation of exciton effect for the design of advanced polymer photocatalysts.

中文翻译：

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光催化制氢与苯甲胺氧化耦合的共价有机框架单原子工程

在光催化中，降低激子结合能并促进激子转化为自由载流子对于增强光催化活性至关重要。这项工作提出了一种在基于腙的二维共价有机骨架（TCOF）上设计Pt单原子的简便策略，以促进H _{2 的}产生以及苯甲胺的选择性氧化。具有 3 wt% Pt 单原子的优化 TCOF-Pt SA 光催化剂表现出优于 TCOF 和 TCOF 负载的 Pt 纳米粒子催化剂的性能。TCOF-Pt SA3上的H ₂和N-亚苄基苄胺的产率分别是TCOF上的12.6倍和10.9倍。经验表征和理论模拟表明，原子分散的Pt通过配位的N ₁ -Pt-C ₂位点稳定在TCOF载体上，从而引起局部极化并提高介电常数，从而达到低激子结合能。这些现象导致促进激子解离成电子和空穴，并加速光激发电荷载流子从本体到表面的分离和传输。这项工作为先进聚合物光催化剂的设计提供了激子效应调节的新见解。