The AFM images were taken in ambient air by Bruker Dimension Icon ScanAsyst with PeakForce mode. The SEM images were collected on a FEI Magellan 400 XHR scanning electron microscope operating at 5 kV, 25 pA below 9 x10 -5 mbar with UC mode. The XRD data were collected using a PANalytical X'Pert PRO XRD system with Cu Ka radiation. The XPS data were collected using XPS: PHI VersaProbe 4 with a monochromatized Al (Ka) source and dual-gun neutralizing system. UPS was collected inside PHI VersaProbe 4 with an incident light energy of 21.22 eV (He I source).