Cellulose scaffolds modulated synthesis of Co3O4 nanocrystals: preparation, characterization and properties

Magnetic Co 3 O 4 nanoparticles were prepared by using microporous regenerated cellulose films as sacrificial scaffolds. The cellulose macromolecules and the porous structure of the films made them used as spatially confined reacting sites where Co(OH) 2 nanoparticles could be synthesized in situ. When the cellulose matrix was removed by sintering at 500 °C, Co 3 O 4 nanoparticles were obtained. XRD and XPS indicated that the prepared nanoparticles were pure Co 3 O 4 without any impurity. TEM and SEM images revealed that the particle size of the nanoparticles was smaller than 100 nm. The nanoparticles had weak ferromagnetic properties at 25 °C. Furthermore, the pronounced quantum confinement effects of the synthesized nanoparticles have been observed, the optical bandgap energies determined were about 1.92 ~ 2.12 and 2.74 ~ 2.76 eV for O 2− → Co 3+ and O 2− → Co 2+ charge-transfer processes, respectively. Furthermore, the resulted Co 3 O 4 nanoparticles behaved stable electrochemical performance with promising applications in the electrode for lithium ion battery.