当前位置: X-MOL 学术J. Phys. Chem. Lett. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Catching the Reversible Formation and Reactivity of Surface Defective Sites in Metal–Organic Frameworks: An Operando Ambient Pressure-NEXAFS Investigation
The Journal of Physical Chemistry Letters ( IF 4.8 ) Pub Date : 2021-09-16 , DOI: 10.1021/acs.jpclett.1c02585
Luca Braglia 1 , Francesco Tavani 2 , Silvia Mauri 1 , Raju Edla 1, 3 , Damjan Krizmancic 1 , Alessandro Tofoni 2 , Valentina Colombo 4 , Paola D'Angelo 2 , Piero Torelli 1
Affiliation  

In this work, we apply for the first time ambient pressure operando soft X-ray absorption spectroscopy (XAS) to investigate the location, structural properties, and reactivity of the defective sites present in the prototypical metal–organic framework HKUST-1. We obtained direct evidence that Cu+ defective sites form upon temperature treatment of the powdered form of HKUST-1 at 160 °C and that they are largely distributed on the material surface. Further, a thorough structural characterization of the Cu+/Cu2+ dimeric complexes arising from the temperature-induced dehydration/decarboxylation of the pristine Cu2+/Cu2+ paddlewheel units is reported. In addition to characterizing the surface defects, we demonstrate that CO2 may be reversibly adsorbed and desorbed from the surface defective Cu+/Cu2+ sites. These findings show that ambient pressure soft-XAS, combined with state-of-the-art theoretical calculations, allowed us to shed light on the mechanism involving the decarboxylation of the paddlewheel units on the surface to yield Cu+/Cu2+ complexes and their reversible restoration upon exposure to gaseous CO2.

中文翻译:

捕捉金属-有机框架中表面缺陷位点的可逆形成和反应性:操作环境压力-NEXAFS 调查

在这项工作中,我们首次应用环境压力操作软 X 射线吸收光谱 (XAS) 来研究原型金属有机框架 HKUST-1 中存在的缺陷位点的位置、结构特性和反应性。我们获得了直接证据,表明在 160 °C 对 HKUST-1 粉末形式进行温度处理后会形成 Cu +缺陷位点,并且它们主要分布在材料表面上。此外,由温度诱导的原始 Cu 2+ /Cu 2+的脱水/脱羧产生的 Cu + /Cu 2+二聚体配合物的全面结构表征报告了桨轮单元。除了表征表面缺陷外,我们还证明了 CO 2可以从表面缺陷的 Cu + /Cu 2+位点可逆地吸附和解吸。这些发现表明,环境压力 soft-XAS 与最先进的理论计算相结合,使我们能够阐明涉及表面桨轮单元脱羧生成 Cu + /Cu 2+配合物和它们在暴露于气态 CO 2 后可逆地恢复。
更新日期:2021-09-23
down
wechat
bug