The microscopic structure information was characterized by a field emission scanning electron microscopy (FESEM, Hitachi, S-4800, Japan) and a high-resolution transmis- sion electron microscopy (HRTEM, JEOL, JEM-2010 HR, Japan).
The microscopic structure information was characterized by a field emission scanningelectron microscopy (FESEM, Hitachi, S-4800, Japan) and a high-resolution transmis- sion electron microscopy (HRTEM, JEOL, JEM-2010 HR, Japan).