fig4

Figure 4. (A and B) A series of XPS spectra of C1s and Fe2p core levels of the C₂₄H₂₄FeNP-GO sheets as a function of reaction time; (C) The Fe/C ratios obtained from the XPS spectra of GO nanosheets reacted with C₂₄H₂₄FeNP (red open circle) and AFc molecules (blue open circle) as a function of reaction time; (D) Magnetization curves of C₂₄H₂₄FeNP-GO sheets (reaction time: 96 h), GO sheets, and solid C₂₄H₂₄FeNP molecular powder at 2 K; (E) $$ \chi_{\mathrm{FD}}^{-1} $$(T) plotted against T for C₂₄H₂₄FeNP-GO (reaction time: 96 h) (red open circle) and AFc-GO (reaction time: 24 h) (blue open circle) sheets. The solid line showing linear fitting to the data according to the Currie-Weiss law. XPS: X-ray photoelectron spectroscopy; GO: graphene oxide; AFc: amino-ferrocene.