TEM_Image_CPY131_repro_calc

The nanoparticles were provided from the Schulz-Group. Synthesis description: For the synthesis of spherical Co₃O₄ nanoparticles, 1.164 g Co(NO₃)₂·6 H₂O (4.0 mmol) was dissolved in 200 mL water in an open reactor vessel. Subsequently, 3.24 mL of ammonium hydroxide solution and 240 µL of H₂O₂ were added. The black reaction mixture was then heated to 60 °C for 15 minutes. A solution containing 0.58 g Co(NO₃)₂·6 H₂O (2 mmol) dissolved in 80 mL water was added and the reaction temperature was maintained at 60 °C for 3 hours. After cooling to room temperature, the nanoparticles were collected by centrifugation at 3000 rpm, washed with water and acetone and dried in air. The particles were then heated at a rate of 4.5 °C min^-1 to 300 °C, where the temperature was maintained for 15 minutes before cooling to room temperature.