Preparation of Gallium Sulfide Nanosheets by Liquid Exfoliation and Their Application As Hydrogen Evolution Catalysts
Preparation of Gallium Sulfide Nanosheets by Liquid Exfoliation and Their Application As Hydrogen Evolution Catalysts
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DOI：
10.1021/acs.chemmater.5b00910
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发表时间：
2015-05-12
影响因子：
8.6
通讯作者：
Coleman, Jonathan N.
中科院分区：
文献类型：
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作者：
Harvey, Andrew;Backes, Claudia;Coleman, Jonathan N.
在这里，我们演示了通过层状 GaS 粉末的液体剥离来生产大量硫化镓 (GaS) 纳米片。通过在合适的溶剂中对粉末进行超声处理来实现剥落。分散浓度随溶剂的变化与经典溶液热力学一致，并表明成功的溶剂是希尔德布兰德溶解度参数接近 11.5 MPa1/2 的溶剂。通过这种方式，可以生产浓度高达 0.2 mg/mL 的纳米片，横向尺寸和厚度分别为 50-1000 nm 和 3-80 层。尽管在边缘附近观察到氧，但纳米片似乎相对无缺陷。使用受控离心技术，可以制备含有尺寸选定的纳米片的分散体。光谱测量表明，分散体的光学性质随纳米片尺寸的变化而变化，从而可以阐明用于原位估计纳米片尺寸和厚度的光谱指标。这些技术可以生产尺寸受控的纳米片，这对于某些应用非常重要。为了证明这一点，我们制备了三种不同尺寸的 GaS 纳米片薄膜，用作析氢电催化剂。我们发现性能和尺寸之间存在明显的相关性，表明小纳米片更有效。这与位于纳米片边缘的催化活性位点一致。
Here, we demonstrate the production of large quantities of gallium sulfide (GaS) nanosheets by liquid exfoliation of layered GaS powder. The exfoliation was achieved by sonication of the powder in suitable solvents. The variation of dispersed concentration with solvent was consistent with classical solution thermodynamics and showed successful solvents to be those with Hildebrand solubility parameters close to 11.5 MPa1/2. In this way, nanosheets could be produced at concentrations of up to similar to 0.2 mg/mL with lateral sizes and thicknesses of 50-1000 nm and 3-80 layers, respectively. The nanosheets appeared to be relatively defect-free although oxygen was observed in the vicinity of the edges. Using controlled centrifugation techniques, it was possible to prepare dispersions containing size-selected nanosheets. Spectroscopic measurements showed the optical properties of the dispersions to vary,strongly with nanosheet size, allowing the elucidation of spectroscopic metrics for in Situ estimation of nanosheet size and thickness. These techniques allow the production of nanosheets with controlled sizes, which will be important for certain applications. To demonstrate this, we prepared films of GaS nanosheets of three different sizes for use as hydrogen evolution electrocatalysts. We found a clear correlation between performance and size, showing small nanosheets to be more effective. This is consistent with the catalytically active sites residing on the nanosheet, edges.