fig4

Figure 4. (A) NH₃ yields and FEs of different catalysts obtained in 0.1 M Na₂SO₄; (B) C_dl and (C) Nyquist plots of Fe₂O₃/FeNC and NC; (D) Optimal NH₃ yields and FEs of Fe₂O₃/FeNC obtained in different electrolytes; (E) Time-dependent current density curve of Fe₂O₃/FeNC for 12 h (inset: NH₃ yields and FEs before and after 12-hour electrolysis); (F) Consecutive recycling tests of Fe₂O₃/FeNC at -0.5 V vs. RHE with the error line represents the standard deviation; (G) SEM image of carbon cloth supported Fe₂O₃/FeNC electrode after long-term electrolysis; (H) The TEM image with inset showing HRTEM image of Fe₂O₃/FeNC with larger magnification after long-term electrolysis (I) EDS-mapping images of Fe₂O₃/FeNC after long-term electrolysis. FEs: Faradaic efficiencies; C_dl: double-layer capacitance; SEM: scanning electron microscope; TEM: transmission electron microscopy; HRTEM: high-resolution TEM; EDS: energy-dispersive X-ray spectroscopy.