Fig. 2: Characterization of restacked Ni-pPD@rGO nanosheets and MOGMs.

a AFM image shows the spontaneously restacked Ni-pPD@rGO nanosheets. b, c HRTEM images of the edge of restacked Ni-pPD@rGO nanosheets, illustrating the interlayer spacing of 0.96 nm between two neighboring rGO and atomic-scale graphene capillaries created by restacking. d The optimized structure of restacked Ni-pPD@rGO nanosheets computed by DFT, with the interlayer spacing labeled by a red arrow and the free space marked by slash lines. e Water contact angle and XRD spectra of MOGMs and GOMs. f Pore size distribution of MOGMs. g Schematic of the sub-nano pathways to conduct water molecules in MOGMs. Green: bottom Ni-pPD nano-islands; Yellow: top Ni-pPD nano-islands; Pink-shaded frames: fully blocked regions by the restacking of two Ni-pPD nano-islands.