综述了南京大学纳米磁学研究组在单层MoS_2量子点研究工作中的最新进展.采用多次Li离子插层的方法成功制备出平均尺寸在3 nm左右的单层MoS_2量子点,超声加热使量子点的结构由1T相向2H相转变,在300 nm紫外光的激发下光致发光强度显著增强;随着激发波长的改变,410 nm左右的发光峰位位移较小,说明量子点尺寸均匀.析氢催化活性研究表明,相比于块体及MoS_2纳米片,MoS_2量子点表现出更佳的析氢催化性能,具有较低的起始过电位(120 mV)和较小塔费尔斜率(69 mV·dec~(-1)),表现出更快的析氢催化速率.MoS_2量子点之所以具有优良的析氢催化性能,是因为其具有大量的活性边界.
This article presented a review of our recent investigations covering the synthesis,structures,optical and electrocatalytic properties of monolayer MoS2 quantum dots. An effective multi-exfoliation method based on lithium (L i) intercalation had been demonstrated for preparing monolayer molybdenum disulfide (MoS2 ) quantum dots (QDs). The average size of the quantum dots was 3 nm, and most of them were single layer. After heating treatment,the crystal structure changed from 1T phase to 2H phase, and the photoluminescence (PL) intensity excited at 300 nm increased remarkably. For the sample with annealing treatment ,the PL at 410 nm was almost not changed even at various excitation wavelengths,indicating that the size of MoS2 QDs was uniform. Compared to the MoS2 bulk and nanosheets,the obtained monolayer MoS2 QDs exhibited the improved catalytic activities for hydrogen evolution reaction (HER) with a low overpotential of approximately 120 mV and a relatively small Tafel slope of 69 mV ·dee-1. Through the analysis and comparison, a better hydrogen evolution performance of MoS2 quantum dots was derived from the abundance of exposed active edge sites.