Walter Schottky Institut and Physik-Department, Technische Universität München , Am Coulombwall 4a, 85748 Garching, Germany.
Nanosystems Initiative Munich (NIM) , Munich 80799, Germany.
ACS Nano. 2015 Nov 24;9(11):11302-9. doi: 10.1021/acsnano.5b04979. Epub 2015 Nov 9.
MoS2 crystals exhibit excellent catalytic properties and great potential for photocatalytic production of solar fuels such as hydrogen gas. In this regard, the photocatalytic stability of exfoliated single- and few-layer MoS2 immersed in water is investigated by μ-Raman spectroscopy. We find that while the basal plane of MoS2 can be treated as stable under photocatalytic conditions, the edge sites and presumably also defect sites are highly affected by a photoinduced corrosion process. The edge sites of MoS2 monolayers are significantly more resistant to photocatalytic degradation compared to MoS2 multilayer edge sites. The photostability of MoS2 edge sites depends on the photon energy with respect to the band gap in MoS2 and also on the presence of oxygen in the electrolyte. These findings are interpreted in the framework of an oxidation process converting MoS2 into MoOx in the presence of oxygen and photoinduced charge carriers. The high stability of the MoS2 basal plane under photocatalytic treatment under visible light irradiation of extreme light intensities on the order of P ≈ 10 mW/μm(2) substantiates MoS2's potential as photocatalyst for solar hydrogen production.
二硫化钼晶体表现出优异的催化性能，在光催化生产太阳能燃料（如氢气）方面具有巨大的潜力。在这方面，通过微拉曼光谱研究了浸在水中的剥离的单原子层和少层二硫化钼的光催化稳定性。我们发现，虽然 MoS2 的基面在光催化条件下可以被视为稳定的，但边缘位点和可能的缺陷位点受到光诱导腐蚀过程的高度影响。MoS2 单层的边缘位点与 MoS2 多层边缘位点相比，对光催化降解具有更高的稳定性。MoS2 边缘位点的光稳定性取决于相对于 MoS2 带隙的光子能量，以及电解质中氧气的存在。这些发现是在氧化过程的框架内解释的，该过程将 MoS2 在氧气存在下和光诱导电荷载流子的作用下转化为 MoOx。在可见光照射下，光强度极端的情况下（约为 P ≈ 10 mW/μm(2)），MoS2 基片在光催化处理下的高稳定性证实了 MoS2 作为太阳能制氢光催化剂的潜力。
