Ketones as Molecular Co-catalysts for Boosting Exciton-Based Photocatalytic Molecular Oxygen Activation
Ketones as Molecular Co-catalysts for Boosting Exciton-Based Photocatalytic Molecular Oxygen Activation
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酮作为分子助催化剂促进基于激子的光催化分子氧活化
DOI：
10.1002/anie.202003042
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发表时间：
2020-04-30
影响因子：
16.6
通讯作者：
Xie Yi
中科院分区：
文献类型：
--
作者：
Wang Hui;Jiang Shenlong;Xie Yi
半导体中的激子过程为追求光催化有机合成开辟了可能性。然而，半导体中自旋弛豫不足和强非辐射衰变限制了这些反应的量子产率和选择性。本文以聚氮化碳（PCN）/丙酮为原型体系，研究了脂肪酮作为分子助催化剂，促进自旋翻转跃迁和抑制非辐射能量损失的作用.光谱研究表明，PCN中的热激子可以转移到酮中，而酮中的三重态激子可以转移到PCN中。因此，PCN/酮系统表现出相当大的三重态激子积累和扩展的可见光响应，从而在基于激子的双光子发射中产生优异的性能，例如单线态氧的产生。这项工作提供了在半导体/分子系统的能量收集的基本理解，并铺平了道路，通过分子助催化剂设计优化激子为基础的双稳态。
Excitonic processes in semiconductors open up the possibility for pursuing photocatalytic organic synthesis. However, the insufficient spin relaxation and robust nonradiative decays in semiconductors place restrictions on both quantum yield and selectivity of these reactions. Herein, by taking polymeric carbon nitride (PCN)/acetone as a prototypical system, we propose that extrinsic aliphatic ketones can serve as molecular co-catalysts for promoting spin-flip transition and suppressing non-radiative energy losses. Spectroscopic investigations indicate that hot excitons in PCN can be transferred to ketones, while triplet excitons in ketones can be transferred to PCN. As such, the PCN/ketone systems exhibit considerable triplet-exciton accumulation and extended visible-light response, leading to excellent performance in exciton-based photocatalysis, such as singlet oxygen generation. This work provides a fundamental understanding of energy harvesting in semiconductor/molecule systems, and paves the way for optimizing exciton-based photocatalysis via molecular co-catalyst design.