金属有机框架的质子,电子和原子转移热力学,Ti-MIL-125与结构障碍本质相关
Nazmiye Gökçe Altınçekiç1, Chance W Lander1, Jiaqi Yu2
1Department of Chemistry and Biochemistry, The University of Oklahoma, Norman, Oklahoma 73019, United States.
Journal of the American Chemical Society
|September 13, 2025
概括
金属有机框架 (MOF) 的晶体大小影响结构乱,并改变质子/电子/原子转移热力学. 较小的晶体表现出更大的混乱,影响了催化活性,并挑战了单位催化剂假设.
科学领域:
- 材料科学:专注于新材料的合成和表征.
- 催化:研究对能源和化学应用至关重要的界面电荷转移反应.
- 纳米技术:研究晶体大小对材料特性和反应性的影响.
背景情况:
- 介面电荷转移反应是异质催化和能量转换的基础.
- 具有氧化还原活性节点的金属有机框架 (MOF) 为研究这些反应提供了精确的控制.
- 基于的MOF,如Ti-MIL-125,模仿TiO2的催化特性.
研究的目的:
- 研究Ti-MIL-125 MOF的不同晶体大小如何影响电荷转移热力学.
- 阐明结构失调与质子,电子和原子转移的热力学之间的关系.
- 评估纳米MOF单位催化剂假设的有效性.
主要方法:
- 用可控的不同晶体大小合成Ti-MIL-125 MOF.
- 电化学开放电路电位 (EOCP) 测量以确定氧化还原反应热力学.
- 分析局部结构变化及其对键解离自由能量 (BDFE) 的计算.
主要成果:
- 在Ti-MIL-125中的晶体大小变化会导致Ti-oxo节点的不同程度的结构障碍.
- 原子转移 (HAT) 反应热力学 (Ti3+O-H BDFE) 取决于大小,在较小的晶体中随着混乱而增加.
- 通过pKa和带间隙探测的质子/电子转移 (PT/ET) 热力学也受到晶体大小的显著影响.
结论:
- 结构性障碍, 不仅仅是缺失链接器的缺陷, 是纳米MOF改变热力学的关键.
- 对于具有显著结构障碍的纳米MOF,单位催化剂假设受到挑战.
- 这些发现对理解金属氧化物如TiO2和其他氧化还原活性MOF的催化有意义.
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