| 초록 |
Atomically thin MoS2 monolayer has the maximized surface area to volume ratio, which encourages various surface chemistry and dynamics. MoS2 with large surface area is also regarded as one of the most promising electrocatalyst for hydrogen evolution reaction (HER) due to its excellent charge carrier mobility and HER activity. HER active sites of edge, S vacancy, and strained S vacancy of MoS2 layer are considered to catalyze the H2 evolution process under the applied reduction potential, confirmed by diverse analytical tools. However, MoS2 modification for analyzing the effect of each active site cannot alter the density of only-one type of the active site. In this respect, independent analysis for each of the active sites is essential for comparison of their intrinsic HER activities. Herein, we implement real-time observation of MoS2 layer during HER by using in situ liquid phase transmission electron microscopy (LPTEM), which promotes the comparative analysis for HER activities of the active sites. Moreover, we demonstrate that HER activity can be determined by the competitive surface wetting between the as-formed H2 bubble and liquid electrolyte on the surface of MoS2 monolayer. |
