关键词: MoS₂, 边缘, 纳米电极, 氢析出反应

Abstract:

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.

Key words: MoS₂, edges, nanoelectrodes, hydrogen evolution reaction.