Thickness Dependence and Percolation Scaling of Hydrogen Production Rate in MoS2 Nanosheet and Nanosheet–Carbon Nanotube Composite Catalytic Electrodes

详细信息    查看全文

• 作者：David McAteer ; Zahra Gholamvand ; Niall McEvoy ; Andrew Harvey ; Eoghan O’Malley ; Georg S Duesberg ; Jonathan N Coleman
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：January 26, 2016
• 年：2016
• 卷：10
• 期：1
• 页码：672-683
• 全文大小：580K
• ISSN：1936-086X

文摘

Here we demonstrate that the performance of catalytic electrodes, fabricated from liquid exfoliated MoS₂ nanosheets, can be optimized by maximizing the electrode thickness coupled with the addition of carbon nanotubes. We find the current, and so the H₂ generation rate, at a given potential to increase linearly with electrode thickness to up ～5 μm after which saturation occurs. This linear increase is consistent with a simple model which allows a figure of merit to be extracted. The magnitude of this figure of merit implies that approximately two-thirds of the possible catalytically active edge sites in this MoS₂ are inactive. We propose the saturation in current to be partly due to limitations associated with transporting charge through the resistive electrode to active sites. We resolve this by fabricating composite electrodes of MoS₂ nanosheets mixed with carbon nanotubes. We find both the electrode conductivity and the catalytic current at a given potential to increase with nanotube content as described by percolation theory.