Figure 3.

a Schematics of formation of SnO2/C coaxial hollow nanospheres; b, c SEM images of SnO2/C coaxial hollow nanospheres; d, e TEM images of SnO2/C coaxial hollow nanospheres; f SEM image of double-shelled SnO2 hollow nanospheres; g TEM image of double-shelled SnO2 hollow nanospheres [38]. Copyright Wiley–VCH Verlag Gmbh & Co. KGaA. Reproduced with permission

Liu and Xue Nanoscale Research Letters 2010 5:1525-1534   doi:10.1007/s11671-010-9728-5