基于两个[2Fe2S]化合物的光催化分解水产氢性能及可能的机理  

Performance and Possible Mechanism of Photocatalytic Water Splitting for Hydrogen Production Based on Two [2Fe2S] Compounds

作　　者：郑会勤 樊耀亭[2] ZHENG Huiqin;FAN Yaoting(College of Environment,Henan Finance University,Zhengzhou 450046,China;College of Chemistry,Zhengzhou University,Zhengzhou 450001,China)

机构地区：[1]河南财政金融学院环境学院,郑州450046 [2]郑州大学化学学院,郑州450001

出　　处：《材料导报》2023年第9期198-205,共8页Materials Reports

基　　金：国家自然科学基金(21171147);河南省青年骨干教师项目(2020GGJS266);河南省高等学校重点科研项目(21B150001)。

摘　　要：本工作合成了两个新的含有桥联配体6,8-硫辛酸甲酯(pdte)的[2Fe2S]化合物1和2,并通过IR、~1HNMR、^(31)PNMR(化合物2)、元素分析、X射线单晶衍射(化合物1)等手段表征了其结构,构建了以目标化合物1或2为光催化剂、EY^(2-)为光敏剂、TEA为电子给体和质子源的三组分光催化体系。结果表明:在pH=11的CH_(3)CN/H_(2)O(V(CH_(3)CN)/V(H_(2)O)=1/1)溶液中和经过3.5 h的可见光(λ>420 nm)照射的条件下,该体系的最大氢产量分别为106.5μmol (TON 13.3 vs.1)和136.2μmol (TON 17 vs.2),对应的产氢速率分别为7 607μmol·g^(-1)·h^(-1)和6 595.6μmol·g^(-1)·h^(-1)。机理研究表明:体系失活主要归因于光催化过程中光敏剂EY^(2-)和催化剂的光降解。在所构建的体系中,光生电子可经两种途径由^(1*)EY^(2-)或EY^(3-)·转移到Fe^(Ⅰ)Fe^(Ⅰ)中心上,形成产氢的重要中间体Fe^(Ⅰ)Fe~0物种,并通过进一步质子化产生HFe^(Ⅱ)Fe^(Ⅰ)物种和(η~2-H_(2))Fe^(Ⅱ)-Fe^(Ⅰ)物种,最终释放出H_(2)分子并使Fe^(Ⅰ)Fe^(Ⅰ)物种再生。这说明目标催化剂(特别是化合物2)可作为潜在的光催化产氢分子催化剂。Two new [2Fe2S] compounds 1 and 2 containing the bridging ligand 6,8-lipoic acid methyl ester(pdte) were synthesized,and their structures were characterized by IR,~1HNMR,~(31)PNMR(compound 2),elemental analysis and X-ray single crystal diffraction(compound 1),etc.A three-component photo-catalytic hydrogen production system was constructed,in which compounds 1 or 2 was used as the photo-catalyst,EY~(2-)as the photo-sensitizer,TEA as the electron donor and proton source,respectively.The results showed that the maximum hydrogen production was 106.5 μmol(TON 13.3 vs.1) and 136.2 μmol(TON 17 vs.2),with corresponding hydrogen production rates 7 607 μmol·g~(-1)·h~(-1)and 6 595.6 μmol·g~(-1)·h~(-1),respectively,under the optimal hydrogen production conditions of V(CH_3CN)/V(H_2O)=1/1,pH=11,and visible light(λ420 nm) irradiation for 3.5 h.Probing into the mechanism of hydrogen production,it was shown that the deactivation of the system was mainly due to the photo-degradation of the photo-sensitizer EY~(2-)and the catalyst in the photo-catalytic process.Photogenerated electrons can be transferred from ~(1*)EY~(2-) or EY~(3-)· to the Fe~ⅠFe~Ⅰ center via two pathways to form the important intermediate Fe~ⅠFe~0 species in the present system.Furthermore,the important hydrogen-producing active intermediates HFe~ⅡFe~Ⅰ species and(η~2-H_2) Fe~Ⅱ-Fe~Ⅰ species were formed by further protonation,finally releasing H_(2) and regenerating Fe~ⅠFe~Ⅰspecies.The result implicated that the title catalyst(especially 2) was a potential molecular catalyst for photo-catalytic hydrogen production.

关 键 词：[2Fe2S]化合物 光催化 产氢 电化学 荧光淬灭 机理 

分 类 号：O641.4[理学—物理化学]