Fig. 1: Two-dimensional (2D) NaCl2 crystal with sandwiched structure in graphene oxide membranes with positive surface potential (p-GO).
From: Two-dimensional anion-rich NaCl2 crystal under ambient conditions
a Schematic design of a p-GO membrane with a positively charged surface prepared by functionalizing GO with polyethyleneimine (PEI). The surface of p-GO exhibits a more favorable attraction to Cl− than to Na+. b Dark-field transmission electron microscopy (TEM) images of ultrathin Na–Cl@p-GO membranes. c (i) High-resolution TEM (HR-TEM) of NaCl2 single crystal; (ii) Fast Fourier transform (FFT) of the entire bright-field image (FFT of NaCl2 and p-GO are marked by red dashed lines and blue dashed lines, respectively); and (iii) inverse FFT (iFFT) of the localized area, showing a hexagonal lattice pattern with six first-order maxima points at (1 ± 0.03)/7.22 nm−1. d Ratios of Na to Cl in p-GO membranes determined by TEM energy-dispersive X-ray spectroscopy (EDS) (details in Supplementary Information section PS4). The red dashed line is the fit of the distribution of rations.
