(Invited) Electrons in Two-Dimensional Materials: Mobility and Catalysis

Abstract

Two-dimensional (2D) materials possess attractive properties for many applications such as (opto)electronics and electrocatalysis. However, their developments are impeded by a number of significant challenges, many of which root in the 'problems of electrons'. On the physics side, the electrons/holes in current 2D semiconductors do not move fast enough under electric field (i.e. low mobility), impeding their use in high-performance electronics and optoelectronics. On the chemistry side, the current 2D electrocatalysts still suffer from relatively low activity/selectivity, hindering their use in efficient energy conversion. These challenges urge for an improved understanding of the electrons in 2D materials, and using these insights to design/discover 2D host materials with better performance.Here I will discuss our recent progress in understanding the physics and chemistry of electrons in 2D materials, including: (1) why 2D semiconductors tend to have a low mobility, and the guidelines towards high-mobility semiconductor [1,2]; (2) the effects of surface charge [3] and water molecules on electrocatalysis, with which we can explain some puzzles in electrochemical CO2 reduction catalyzed by single metal atom in graphene [4] .[1] L. Cheng, Y. Liu, JACS, 2018 DOI: 10.1021/jacs.8b07871[2] L. Cheng, C. Zhang, Y. Liu, JACS 2019 DOI: 10.1021/jacs.9b05923[3] D. Kim, J. Shi, Y. Liu, JACS, 2018, 140, 9127[4] X. Zhao, Y. Liu, in preparation