光催化
苯
水溶液
苯酚
吸附
羟基化
过氧化氢
化学
羟基自由基
光化学
共价有机骨架
化学工程
材料科学
共价键
催化作用
激进的
有机化学
工程类
酶
作者
Shijian Zhou,Yuexin Shi,Peng Huang,Weiguo Kong,Hao Hu,Haoran Xie,Changlai Li,Jiang Qin,Zewu Zhang,Luming Peng,Xiaokang Ke,Yan Kong
标识
DOI:10.1016/j.cej.2023.146946
摘要
Structural design is important and challenging for the fabrication of covalent organic frameworks (COFs) in the photocatalytic applications. Hydroxyl groups have been found to be the active sites for O2 adsorption and promote the electron-donating conjugation effects, which favorable for the oxygen reduction reaction (ORR) in photocatalytic hydrogen peroxide (H2O2) evolution. This study reports the preparation of “fragmentized” COFs (TxHy-COFs) photocatalysts and their application in H2O2 synthesis, as well as the direct hydroxylation of benzene to phenol. The results demonstrate that the functional design of surface hydroxyl (–OH) modification on fragmentized TxHy-COFs was achieved by varying the feed ratio of TAPT and THTA monomers, which greatly enhances surface hydrophilicity and effectively improves the separation and transfer of photoexcited electrons and holes. Under visible light irradiation without sacrificial agents, the fragmentized T1H1.8-COF exhibits a boosting H2O2 yield of 2567 μmol g−1h−1, which is 4.2 times higher than the original T1H1-COF. Furthermore, the introduction of metal ions (Fe3+ etc.) into the COF framework through the impregnation method enables the in situ activation of H2O2, allowing the direct hydroxylation of benzene to phenol in aqueous systems, with yield of 9.4 % and selectivity of 99 %. The results of this work demonstrate that the prepared photocatalyst exhibits high stability and photocatalytic activity by structural design optimization, showing great potential for industrial applications in H2O2 production and direct photo-oxidation.
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