Preparation of high-percentage 1T-phase transition metal dichalcogenide nanodots for electrochemical hydrogen evolution

• Main Authors: Tan, Chaoliang, Luo, Zhimin, Chaturvedi, Apoorva, Cai, Yongqing, Du, Yonghua, Gong, Yue, Huang, Ying, Lai, Zhuangchai, Zhang, Xiao, Zheng, Lirong, Qi, Xiaoying, Goh, Min Hao, Wang, Jie, Han, Shikui, Wu, Xue-Jun, Gu, Lin, Kloc, Christian, Zhang, Hua
• Other Authors: School of Materials Science & Engineering
• Format: Article
• Language: English
• Published: 2020
• Subjects: Engineering::Materials; Hydrogen Evolution; Metallic 1T Phase
• Online Access: https://hdl.handle.net/10356/138720
• Institution: Nanyang Technological University

Nanostructured transition metal dichalcogenides (TMDs) are proven to be efficient and robust earth-abundant electrocatalysts to potentially replace precious platinum-based catalysts for the hydrogen evolution reaction (HER). However, the catalytic efficiency of reported TMD catalysts is still limited by their low-density active sites, low conductivity, and/or uncleaned surface. Herein, a general and facile method is reported for high-yield, large-scale production of water-dispersed, ultrasmall-sized, high-percentage 1T-phase, single-layer TMD nanodots with high-density active edge sites and clean surface, including MoS2 , WS2 , MoSe2 , Mo0.5 W0.5 S2 , and MoSSe, which exhibit much enhanced electrochemical HER performances as compared to their corresponding nanosheets. Impressively, the obtained MoSSe nanodots achieve a low overpotential of -140 mV at current density of 10 mA cm-2 , a Tafel slope of 40 mV dec-1 , and excellent long-term durability. The experimental and theoretical results suggest that the excellent catalytic activity of MoSSe nanodots is attributed to the high-density active edge sites, high-percentage metallic 1T phase, alloying effect and basal-plane Se-vacancy. This work provides a universal and effective way toward the synthesis of TMD nanostructures with abundant active sites for electrocatalysis, which can also be used for other applications such as batteries, sensors, and bioimaging.