| 慈成刚,董龙,臧杰超,罗国相.化学通报,2020,83(9):837-843. |
| Si取代Keggin型多酸催化光解水产氢机理 |
| Mechanistic Insight into the Photo-splitting of Water to Dihydrogen Catalyzed by Si-Substituted Keggin-type Polyoxometalate |
| 投稿时间：2020-03-24 修订日期：2020-04-04 |
| DOI： |
| 中文关键词: 多酸 光解水 H2产生 反应机理 密度泛函理论 |
| 英文关键词:Polyoxometalates Photo-splitting of water H2-generation Mechanism DFT |
| 基金项目:黔南州社会发展项目（黔南科社字2017-91）、贵州省科技厅项目（黔科合基础[2020]1Y050）和黔南民族师范学院项目（qnsyrc201612，qnsyk201601）资助 |
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| 中文摘要: |
| 本文采用密度泛函理论（DFT）和含时密度泛函理论（TD-DFT）方法研究了Keggin型多酸[SiW12O40]4-催化光解水产氢机理。计算结果显示反应主要包括四个步骤：（1）光激发；（2）电荷转移和生成单电子还原（OER）中间体；（3）生成双电子还原（TER）中间体；（4）氢气从多酸表面解离和催化剂重生。当第一个电子从甲醇转移到多酸后，后续反应均为热力学上有利的放热途径，并推动第二个电子从甲醇自由基、H[SiW12O40]4-或[SiW12O40]5-转移到OER中间体H[SiW12O40]4-或[SiW12O40]5-生成TER中间体[SiW12O40]6-、H[SiW12O40]5-或H2[SiW12O40]4-，并伴随着H2产生。耦合的电子和质子转移路径在能量上最有利。甲醇和水分子的参与有利于H2产生。多酸在整个催化循环中作为光敏剂、催化剂、电子的受体和给体。 |
| 英文摘要: |
| The photo-splitting mechanism of water to obtain H2 by Keggin-type polyoxometalate (POM) [SiW12O40]4- has been investigated using DFT and TD-DFT calculations. The catalytic cycle can be divided into four steps, i.e. (1) photoexcitation, (2) electron transfer and formation of one-electron-reduced (OER) intermediate, (3) formation of two-electron-reduced (TER) intermediate, and (4) H2 release and regeneration of the catalyst. Once an electron is transferred from CH3OH to POM, the following steps are thermodynamically favorable and induce the second electron transfer from ·CH2OH, H[SiW12O40]4-, or [SiW12O40]5- to OER intermediate H[SiW12O40]4- or [SiW12O40]5- to form TER intermediate [SiW12O40]6-, H[SiW12O40]5-, or H2[SiW12O40]4-, and accompanied by the generation of H2. Coupled proton and electron transfer pathway is energetic favorable. The participation of CH3OH and H2O is favorable to form H2. The POM acts as photosensitizer, catalyst, electron reservoir and donner in the entire catalytic cycle. |
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