Fig. 1. Visible colour change of AO7 solution during redox reaction using (a) FeBC and (b) FePC amorphous ribbons.

Fig. 2. UV-vis absorbance spectra of AO7 solutions during the redox reactions using (a) FeBC and (b)FePC amorphous ribbons; (c) normalized concentration change of AO7 solutions during the degradation process; (d) the ln (Ct/C0) vs. time curves for FeBC and FePC amorphous ribbons. (T =298 K, pH = 3, ribbon dosage =2 g/L, and CAO7 = 20 mg/L).

Fig. 3. Synchrotron XRD intensity vs Q plots of the precipitates produced by AO7 solution degradation using as-cast FeBC and FePC amorphous ribbons.

Fig. 4. Surface morphologies of (a) as-cast FeBC ribbon, (b) reacted FeBC ribbon, (c) as-cast FePC ribbon and (d) reacted FePC ribbon.

Fig. 5. Electrochemical behaviour of FeBC and FePC amorphous ribbons in AO7 solutions (T =298 K, pH = 3, and CAO7 = 20 mg/L) (a) polarization curves; (b) Nyquist plots derived from EIS measurements.

Fig. 6. XPS spectra of (a) Fe 2p 3/2, (b) O 1s, (c) C 1s and (d) B 1s in binding energy regions for the FeBC amorphous ribbons before and after degradation.

Fig. 7. XPS spectra of (a) Fe 2p 3/2, (b) O 1s, (c) C 1s and (d) P 2p in binding energy regions for the FePC amorphous ribbons before and after degradation.

Fig. 8. Normalized concentration change of AO7 solutions at different degradation cycles during the redox reactions (a) using FeBC ribbons, (b) using FePC ribbons; derived k at different degradation cycles (c) using FeBC ribbons, (d) using FePC ribbons.

Fig. 9. Synchrotron XRD intensity vs Q plots of (a) the FeBC amorphous ribbons before and after degradation and (b) the FePC amorphous ribbons before and after degradation; (c) the difference curves for △Int = Int before-Int after of FeBC and FePC amorphous ribbons; (d) the synchrotron XRD total structure factors S(q) of as-cast FeBC and FePC amorphous ribbons.

Fig. 10. SEM micrographs show the top views of (a) the FeBC amorphous ribbons after 22 reaction cycles, and (b) the FePC amorphous ribbons after 10 reaction cycles.

Fig. 11. SEM micrographs of the FeBC amorphous ribbons, (a) side view after 22 reaction cycles, with an overall 3D porous nanosheet arrays; (b), (c), (d) the magnified views of the reacted regions.

Fig. 12. Surface morphologies of FeBC amorphous ribbons, (a) after 7 reaction cycles, enlarged image of the section marked in the inset; (c) after 10 reaction cycles; (e) after 22 reaction cycles. Schematic diagram showing the formation process of the nanosheet array structures in FeBC amorphous ribbons, (b) after 7 reaction cycles; (d) after 10 reaction cycles; (f) after 22 reaction cycles, enlarged diagram of the section marked in the inset.

Fig. 13. Effects of (a) pH, (c) ribbon dosage, and (e) dye concentration on the normalized concentration change of AO7 solutions during the redox reactions using FeBC amorphous ribbons. Derived k at different (b) pH, (d) ribbon dosage, and (f) dye concentration using FeBC amorphous ribbons.