Fig. 3: Chemical microenvironments and in-channel interactions in MoS₂-PDDA membranes.

a High-resolution N 1s XPS spectra of MoS₂-PDDA membranes with different PDDA contents. b The composition percentage of C–N⁺ and C–N in the MoS₂-PDDA membrane (12.0 wt.% PDDA) obtained from the deconvoluted results of the high-resolution N 1s XPS spectrum. The inset illustrates the dual chemical environment of QAs within MoS₂ channels. c High-resolution N 1s XPS spectra of the MoS₂-PDDA membrane (12.0 wt.% PDDA) following exposure to water and acid (0.01 M HCl) for 30 days. d Binding energies between MDDA/MDDA, MDDA/1T-MoS₂, and MDDA/2H-MoS₂ determined by DFT calculations. e Binding energies between MDDA/1T-MoS₂ under nanoconfinement as a function of interlayer d-spacing. The inset depicts two parallel 1T-MoS₂ monolayers with tunable interlayer d-spacing, where MDDA is positioned adjacent to one monolayer plane. f Calculated charges of MDDA under different conditions: in bulk, in interaction with a 1T-MoS₂ monolayer, and confined within a 1T-MoS₂ channel featuring a d-spacing of 10 Å. The upper panel displays the charge density differences for MDDA/1T-MoS₂ under nanoconfinement, with yellow and blue areas representing charge accumulation and charge depletion, respectively.