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Uniform Ordered Two-Dimensional Mesoporous TiO2 Nanosheets from Hydrothermal-Induced Solvent-Confined Monomicelle Assembly
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2018-03-05 , DOI: 10.1021/jacs.8b00909
Kun Lan 1 , Yao Liu 1 , Wei Zhang 1 , Yong Liu 1 , Ahmed Elzatahry 2 , Ruicong Wang 1 , Yongyao Xia 1 , Dhaifallah Al-Dhayan 3 , Nanfeng Zheng 4 , Dongyuan Zhao 1
Affiliation  

Two-dimensional (2D) nanomaterials have been the focus of substantial research interest recently owing to their fascinating and excellent properties. However, 2D porous materials have remained quite rare due to the difficulty of creating pores in 2D nanostructures. Here, we have synthesized a novel type of single-layered 2D mesoporous TiO2 nanosheets with very uniform size and thickness as well as ordered mesostructure from an unprecedented hydrothermal-induced solvent-confined assembly approach. The F127/TiO2 spherical monomicelles are first formed and redispersed in ethanol and glycerol, followed by a hydrothermal treatment to assemble these subunits into single-layered 2D mesostructure owing to the confinement effect of highly adhered glycerol solvent. The obtained 2D mesoporous TiO2 nanosheets have a relative mean size at around 500 × 500 nm and can be randomly stacked into a bulk. The TiO2 nanosheets possess only one layer of ordered mesopores with a pore size of 4.0 nm, a very high surface area of 210 m2 g-1 and a uniform thickness of 5.5 nm. The thickness can be further manipulated from 5.5 to 27.6 nm via simply tuning precursor concentration or solvent ratio. Due to the well-defined 2D morphology and large mesoporosity as well as crystalline anatase mesopore walls, these uniform TiO2 nanosheets are capable of providing large accessible voids for sodium ion adsorption and intercalation as well as preventing volume expansion. As expected, these mesoporous TiO2 nanosheets have exhibited an excellent reversible capacity of 220 mAh g-1 at 100 mA g-1 as sodium-ion battery anodes, and they can retain at 199 mAh g-1 after numerous cycles at different current densities. The capacity is retained at 44 mAh g-1 even at a large current density of 10 A g-1 after 10 000 cycles, demonstrating a remarkable performance for energy storage.

中文翻译:

来自水热诱导溶剂限制单体组装的均匀有序二维介孔 TiO2 纳米片

二维 (2D) 纳米材料由于其迷人和优异的特性,最近成为大量研究兴趣的焦点。然而,由于难以在二维纳米结构中形成孔洞,二维多孔材料仍然非常罕见。在这里,我们通过前所未有的水热诱导溶剂限制组装方法合成了一种新型的单层二维介孔 TiO2 纳米片,具有非常均匀的尺寸和厚度以及有序的介孔结构。F127/TiO2 球形单胶束首先形成并重新分散在乙醇和甘油中,然后由于高度粘附的甘油溶剂的限制作用,通过水热处理将这些亚基组装成单层二维细观结构。获得的二维介孔 TiO2 纳米片的相对平均尺寸约为 500 × 500 nm,可以随机堆叠成块状。TiO2 纳米片仅具有一层有序的介孔,孔径为 4.0 nm,具有 210 m2 g-1 的极高表面积和 5.5 nm 的均匀厚度。通过简单地调整前体浓度或溶剂比例,可以进一步控制厚度从 5.5 到 27.6 nm。由于明确的二维形态和大介孔率以及结晶锐钛矿介孔壁,这些均匀的 TiO2 纳米片能够为钠离子吸附和嵌入提供大的可及空隙,并防止体积膨胀。正如预期的那样,这些介孔 TiO2 纳米片作为钠离子电池阳极在 100 mA g-1 下表现出 220 mAh g-1 的优异可逆容量,在不同电流密度下多次循环后,它们可以保持在 199 mAh g-1。即使在 10 A g-1 的大电流密度下经过 10 000 次循环后,容量仍保持在 44 mAh g-1,显示出卓越的储能性能。
更新日期:2018-03-05
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