Porous Two-Dimensional Nanosheets Converted from Layered Double Hydroxides and Their Applications in Electrocatalytic Water Splitting
Porous Two-Dimensional Nanosheets Converted from Layered Double Hydroxides and Their Applications in Electrocatalytic Water Splitting
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DOI：
10.1021/acs.chemmater.5b02177
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发表时间：
2015-08-25
影响因子：
8.6
通讯作者：
Jin, Song
中科院分区：
文献类型：
--
作者：
Liang, Hanfeng;Li, Linsen;Jin, Song
多孔材料由于其高表面积和丰富的边缘位点而特别令人感兴趣，这有利于诸如催化的应用。尽管存在用于合成多孔金属氧化物的成熟策略（例如，通过退火相应的金属氢氧化物），缺乏制备多孔金属氢氧化物和金属硫属化物的简便且可规模化的途径。在这里，我们报告了一个简单的和一般的策略，通过选择性蚀刻层状双氢氧化物（LDH）的纳米片前体，含有两性金属，并进一步将它们转化为多孔金属硫属化物的金属氢氧化物的多孔纳米片的溶液方法。使用NiGa LDH作为一个例子，我们表明，具有高表面可及性的薄纳米片促进NiGa LDH的topotactic转换为β-Ni（OH），并进一步NiSe，多孔纹理，同时保持片状形态。转化的β-Ni（OH）和NiSe 2分别对电催化析氧反应和析氢反应（HER）具有高活性，这证明了这种具有丰富边缘位点的高表面积多孔纳米结构的应用。特别是，多孔NiSe 2纳米片表现出优异的催化活性，对HER与低的起始过电位，小的塔菲尔斜率，并在酸性和碱性条件下良好的稳定性。进一步证明了使用这些多孔β-Ni（OH）（2）和NiSe纳米片的总体电化学水裂解实验。我们的工作提出了一种新的策略，以制备多孔纳米材料，并进一步提高其催化和其他应用。
Porous materials are of particular interest due to their high surface area and rich edge sites, which are favorable for applications such as catalysis. Although there are well-established strategies for synthesizing porous metal oxides (e.g., by annealing the corresponding metal hydroxides), facile and scalable routes to porous metal hydroxides and metal chalcogenides are lacking. Here, we report a simple and general strategy to synthesize porous nanosheets of metal hydroxides by selectively etching layered double hydroxide (LDH) nanoplate precursors that contain amphoteric metal and to further convert them into porous metal chalcogenides by a solution method. Using NiGa LDH as an example, we show that the thin nanoplates with high surface accessibility facilitate the topotactic conversion of NiGa LDH to beta-Ni(OH), and further to NiSe, with porous texture while preserving the sheet-like morphology. The converted beta-Ni(OH), and NiSe2 are highly active for electrocatalytic oxygen evolution reaction and hydrogen evolution reaction (HER), respectively, which demonstrates the applications of such high surface area porous nanostructures with rich edge sites. Particularly, the porous NiSe2 nanosheets exhibited excellent catalytic activity toward HER with low onset overpotential, small Tafel slope, and good stability under both acidic and alkaline conditions. Overall electrochemical water splitting experiments using these porous beta-Ni(OH)(2) and NiSe, nanosheets were further demonstrated. Our work presents a new strategy to prepare porous nanomaterials and to further enhance their catalytic and other applications.