Fig. 9
a Low-magnification SEM image of hollow nanohexagons, b Plane size distribution of hollow nanohexagons, c High-magnification TEM image of hollow nanohexagons, and d High-magnification SEM image of hollow nanohexagons. The inset is the corresponding electronic diffraction pattern from one nanohexagon. Scale bars, a 100 nm, b 5 nm, and c 100 nm [37]