MoS₂作为高效的电催化氢析出(HER)催化剂已有大量文献报道. 实验和DFT计算结果都表明MoS₂的高氢析出活性来源于边缘，而其基面是催化惰性的。为了进一步验证此结论，本文利用巯基羧酸在恒电位下自组装单层修饰的纳/微米电极固定不同尺寸的单个纳米片状，对MoS₂氢析出催化活性与其尺寸的关系进行研究，发现纳米片状MoS₂具有较高的催化活性，同时较小尺寸的MoS₂氢析出活性更高，说明MoS₂的边缘的增多对其催化活性有巨大提升，即证明了边缘部分具有更高的氢析出催化活性.

Molybdenum disulfide (MoS₂) has been acknowledged to play important roles in hydrogen evolution reaction (HER) for hydrogen energy technology. Both computational and experimental results have suggested that the promising catalytic activity of MoS₂ for the HER could be attributed to the sulfur edges of two-dimensional nanosheets, while their basal planes were catalytically inert. In order to verify this conclusion, we prepared single MoS₂ sheet electrodes which were made of individual MoS₂ sheets attached on the self-assembly monolayers (SAM) of SH(CH₂)₁₅COOH at Au ultramicroelectrodes (Au/SAM/MoS₂). The single MoS₂ sheet electrodes were prepared by dipping the SAM-modified Au ultramicroelectrodes in dilute solutions of MoS₂ sheets whose sizes were similar to or slightly smaller than the Au/SAM electrodes. The electrocatalytic properties of the as-prepared single MoS₂sheet electrodes with different sizes for HER were investigated in 0.5 mol·L^-1 H₂SO₄. It is shown that the nanoscale MoS₂ sheets exhibited superior HER activity over the microsize MoS₂ sheets. This is because of the abundantly exposed active sites on the nanoscale MoS₂ and the individual nanosheet could reflect its intrinsic reactivity more exactly. It directly proved that the active sites of MoS₂ in HER were at the edges.