Pore Diameter and Chemistry Modulated Flexible Ion Selectivity through a Single-Layer MoS2 Nanopore

Nanoporous membranes based on 2D materials are promisingas themost efficient technologies for practical engineering applicationssuch as seawater desalination, ion sieving, and gas separation. Inthis work, we utilize various nanopores in molybdenum disulfide (MoS2) membranes to enable flexible ion selectivity that is tunedefficiently by adjusting pore diameter and surface chemistry. We theoreticallyuncover the molecular mechanisms that lead to MoS2 nanoporeswith varied diameters and pore atom chemistry exhibiting distinctlydifferent ion selectivity. MoS2 nanopores with S atomsat the nanopore boundary facilitate K+ ion translocationand rejection of Cl- ions. MoS2 nanoporeswith Mo atoms at the nanopore boundary permit Cl- ion translocation and reject K+ ions. The average flowvelocity of K+ ions in the MoS2 nanopore withS atoms at the nanopore boundary is larger than that of Cl- ions in the MoS2 nanopore with Mo atoms at the nanoporeboundary. This phenomenon is attributed to the totally different iontransport mechanisms modulated by the nanopore boundary atoms. Thiswork provides new insights into designing multifunctional membraneson a single 2D material membrane with flexible and optimal ion selectivitytoward broad applications.