Electronic Modulation of Doped MoS 2 Nanosheets for Improved CO 2 Sensing and Capture.

Transition-metal dichalcogenides (TMDs) are widely used in the gas sensing field, owing to their high surface-to-volume ratio enabled by the two-dimensional (2D) structure, adjustable band gap, and high electron transfer. However, it is challenging for TMD materials to realize superior CO 2 sensing, due to their weak CO 2 adsorption capacity. Herein, we predict through density functional theory (DFT) calculations that rare earth metal doping is an effective strategy to boost the CO 2 sensing capability of TMDs. As a proof-of-concept, we investigate and find that the introduction of rare earth metal atoms (La, Ce, Pr, or Nd) can induce lattice strain and modulate the electronic properties of MoS 2 . When negative charges are injected in rare earth metal doped MoS 2 (R-MoS 2 ), the 5d or 4f orbital of the rare earth metal atom in R-MoS 2 can produce a stronger orbital hybridization with 2p orbitals of C and O in CO 2 . Therefore, the CO 2 adsorption is significantly enhanced and the charge transfer is facilitated for negatively charged R-MoS 2 . Moreover, negatively charged R-MoS 2 exhibits an excellent CO 2 selectivity. Our results indicate that the rare earth metal doping and electronic modulation in 2D materials may provide a new pathway for CO 2 sensing and capture.