Figure 7From: Preparation of Fe3O4Spherical Nanoporous Particles Facilitated by Polyethylene Glycol 4000TEM images of Fe3O4samples of different PEG 4000 amount:a 2 mmol PEG 4000, 30 min at 265 °C;b 2 mmol PEG 4000, 1 h at 265 °C; andc 4 mmol PEG 4000, 30 min at 265 °CBack to article page