Interpreting the role of carbon in phase transformation from β-FeOOH to α-Fe2O3

Abstract In this work, the crystal phase transformation from β-FeOOH to α-Fe2O3 was unraveled t the relationship between structure and performance. It has been verified that the carbon layer can benefit to scaffold the phase transformation from β-FeOOH nanospindles to hollow α-Fe2O3 nanorods. The hollow α-Fe2O3 nanorods with diameter of ∼15 nm were depicted by TEM and BET, and the carbon shell contouring α-Fe2O3 nanorod was further revealed by HRTEM and EDS elemental mapping. The amorphous structural information of the carbon layer was demonstrated by EELS and Raman spectra. The characterizations and analysis unravel the role of carbon in the phase transformation of nanoparticle, which is regarded to intrinsically affect the structure-property of energy storage performance.