College of Science and College of Chemical Engineering , China University of Petroleum , Qingdao 266580 , P. R. China.
ACS Appl Mater Interfaces. 2018 Jul 18;10(28):23721-23730. doi: 10.1021/acsami.8b04026. Epub 2018 Jul 6.
Ultrathin metal-organic framework (MOF) nanosheets possessing inherent advantages of both two-dimensional (2D) features and MOFs are attracting intensive research interest. The direct manufacture of MOF nanosheets is still a challenge up to now. Here, we have developed a novel bottom-up approach to synthesize zeolitic imidazolate framework-67 (ZIF-67) nanosheets, which can be in situ converted into CoO ultrathin nanomeshes after thermal treatment. Interestingly, the obtained CoO nanomeshes are rich in oxygen defects, providing fruitful active sites for the faradaic reaction. The modified electrode exhibits a large specific capacitance (1216.4 F g at 1 A g), as well as a high rate capability (925.5 F g at 20 A g). Moreover, an asymmetric supercapacitor made of CoO//activated carbon shows an energy density of 46.5 Wh kg at 790.7 W kg. Furthermore, the 2D CoO ultrathin nanomeshes show an outstanding performance for the oxygen evolution reaction with an overpotential of 230 mV at the onset potential and a small Tafel slope of 74.0 mV dec. The present method presents a facile avenue to the preparation of other 2D ultrathin metal oxide nanostructures with various applications in energy catalysis and conversion.
具有二维（2D）特征和金属有机骨架（MOF）固有优势的超薄金属有机骨架（MOF）纳米片引起了人们的浓厚兴趣。到目前为止，MOF 纳米片的直接制造仍然是一个挑战。在这里，我们开发了一种新颖的自下而上的方法来合成沸石咪唑酯骨架-67（ZIF-67）纳米片，这些纳米片经过热处理后可以原位转化为 CoO 超薄纳米网。有趣的是，所获得的 CoO 纳米网富含氧缺陷，为法拉第反应提供了丰富的活性位点。修饰后的电极表现出大的比电容（在 1 A g 时为 1216.4 F g）以及高倍率性能（在 20 A g 时为 925.5 F g）。此外，由 CoO//活性炭制成的非对称超级电容器在 790.7 W kg 时具有 46.5 Wh kg 的能量密度。此外，2D CoO 超薄纳米网在析氧反应中表现出优异的性能，其起始电位的过电位为 230 mV，小的塔菲尔斜率为 74.0 mV dec。该方法为制备具有各种能源催化和转化应用的其他二维超薄金属氧化物纳米结构提供了简便的途径。
