Sub-Nanometer Mono-Layered Metal-Organic Frameworks Nanosheets for Simulated Flue Gas Photoreduction.

He, Dong; Wang, Qian; Rong, Yan; Xin, Zhifeng; Liu, Jing-Jing; Li, Qiang; Shen, Kejing; Chen, Yifa · Adv Mater · 2024

basic_science · Level V

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Abstract

The dilemma between the thickness and accessible active site triggers the design of porous crystalline materials with mono-layered structure for advanced photo-catalysis applications. Here, a kind of sub-nanometer mono-layered nanosheets (Co-MOF MNSs) through the exfoliation of specifically designed Co<sub>3</sub> cluster-based metal-organic frameworks (MOFs) is reported. The sub-nanometer thickness and inherent light-sensitivity endow Co-MOF MNSs with fully exposed Janus Co<sub>3</sub> sites that can selectively photo-reduce CO<sub>2</sub> into formic acid under simulated flue gas. Notably, the production efficiency of formic acid by Co-MOF MNSs (0.85 mmol g<sup>-1</sup> h<sup>-1</sup>) is ≈13 times higher than that of the bulk counterpart (0.065 mmol g<sup>-1</sup> h<sup>-1</sup>) under a simulated flue gas atmosphere, which is the highest in reported works up to date. Theoretical calculations prove that the exposed Janus Co<sub>3</sub> sites with simultaneously available sites possess higher activity when compared with single Co site, validating the importance of mono-layered nanosheet morphology. These results may facilitate the development of functional nanosheet materials for CO<sub>2</sub> photo-reduction in potential flue gas treatment.