The morphology of the membranes was analyzed using atomic force microscope (AFM) imaging scanned over a broad region, as shown in Figure . A histogram of the height profile of the membranes indicates that they vary in thickness from 2 -6 nm (Figure (ii)) corresponding to 3 -7 layers (c-axis lattice constant of Hausmannite is 0.947 nm). High-angle annular dark-field images (HAADF) of the membranes acquired using a scanning transmission electron microscope (STEM) are shown in Figures and. We observed that the exfoliated membranes were of cuboidal shape with lateral dimensions ranging from 25 -30 nm (Figure ). The interplanar spacing was found to be 0.49 nm (Figure ) corresponding to the spacing between (101) planes. This is in close agreement with results from DFT calculations that show a layer periodicity of 0.50 nm. In comparison, the results from TEM micrographs of bulk Mn3O4 (Figure ) showed that the sample lateral dimension was 100 -200 nm. We carried out dynamic light scattering (DLS) experiments to further measure the particle-size distribution by dispersing the samples in an ethanol solvent. The histogram plots (Figure ) indicate that the lateral size of the membranes was within a range of 75 -300 nm, which is smaller than the bulk Mn3O4 precipitates that span 250 -600 nm.