School of Chemistry, Faculty of Science, The University of New South Wales, Sydney, New South Wales 2052, Australia.
Nat Commun. 2017 Jun 5;8:15341. doi: 10.1038/ncomms15341.
Two-dimensional metal-organic frameworks represent a family of materials with attractive chemical and structural properties, which are usually prepared in the form of bulk powders. Here we show a generic approach to fabricate ultrathin nanosheet array of metal-organic frameworks on different substrates through a dissolution-crystallization mechanism. These materials exhibit intriguing properties for electrocatalysis including highly exposed active molecular metal sites owning to ultra-small thickness of nanosheets, improved electrical conductivity and a combination of hierarchical porosity. We fabricate a nickel-iron-based metal-organic framework array, which demonstrates superior electrocatalytic performance towards oxygen evolution reaction with a small overpotential of 240 mV at 10 mA cm, and robust operation for 20,000 s with no detectable activity decay. Remarkably, the turnover frequency of the electrode is 3.8 s at an overpotential of 400 mV. We further demonstrate the promise of these electrodes for other important catalytic reactions including hydrogen evolution reaction and overall water splitting.
二维金属有机骨架是一类具有诱人化学和结构特性的材料，通常以块状粉末的形式制备。在这里，我们通过溶解-结晶机制展示了一种在不同基底上制备超薄纳米片阵列金属有机骨架的通用方法。这些材料表现出有趣的电催化性能，包括由于纳米片的超薄厚度而具有高度暴露的活性分子金属位点、改善的导电性以及分级多孔性的结合。我们制备了一种镍铁基金属有机骨架阵列，该阵列在析氧反应中表现出优异的电催化性能，在 10 mA cm 时的过电位仅为 240 mV，并且在 20000 s 的时间内稳定运行，没有可检测到的活性衰减。值得注意的是，在 400 mV 的过电位下，电极的周转频率为 3.8 s。我们进一步证明了这些电极在其他重要催化反应中的应用前景，包括析氢反应和整体水分解。
