化学
吸附
金属有机骨架
电子转移
氧化还原
金属
外层电子转移
氧气
无机化学
物理化学
离子
有机化学
作者
Adam B. Jaffe,Michael E. Ziebel,David M. Halat,Naomi Biggins,Rebecca A. Murphy,Khetpakorn Chakarawet,Jeffrey A. Reimer,Jeffrey R. Long
摘要
Developing O2-selective adsorbents that can produce high-purity oxygen from air remains a significant challenge. Here, we show that chemically reduced metal–organic framework materials of the type AxFe2(bdp)3 (A = Na+, K+; bdp2– = 1,4-benzenedipyrazolate; 0 < x ≤ 2), which feature coordinatively saturated iron centers, are capable of strong and selective adsorption of O2 over N2 at ambient (25 °C) or even elevated (200 °C) temperature. A combination of gas adsorption analysis, single-crystal X-ray diffraction, magnetic susceptibility measurements, and a range of spectroscopic methods, including 23Na solid-state NMR, Mössbauer, and X-ray photoelectron spectroscopies, are employed as probes of O2 uptake. Significantly, the results support a selective adsorption mechanism involving outer-sphere electron transfer from the framework to form superoxide species, which are subsequently stabilized by intercalated alkali metal cations that reside in the one-dimensional triangular pores of the structure. We further demonstrate O2 uptake behavior similar to that of AxFe2(bdp)3 in an expanded-pore framework analogue and thereby gain additional insight into the O2 adsorption mechanism. The chemical reduction of a robust metal–organic framework to render it capable of binding O2 through such an outer-sphere electron transfer mechanism represents a promising and underexplored strategy for the design of next-generation O2 adsorbents.
科研通智能强力驱动
Strongly Powered by AbleSci AI