fig6

Figure 6. (A) Ammonia removal efficiency at different condition of pH and (B) different ammonia concentration; (C) XPS of XAS spectra of Ni L_2,3-edge; (D) Schematic illustration of energy barrier during ammonia adsorption on the surface of Ni-Cu-Fe-OOH and Ni-Cu-OOH; (E) CV profile and (F) Chronoamperometry curves of the NiCuFe electrode and NiCu electrode in 0.5 M NaOH w/wo 55 × 10^-3 NH₄Cl; (G) UV-vis curves of the electrolyte tested for AOR after 12 h, 15 h, 18 h, and 24 h, respectively; (H) Ammonia removal efficiency and Faradaic efficiency of activated NiCuFe electrode under different anode potentials^[111]. This figure is quoted with permission from Zhu et al. XPS: X-ray photoelectron spectroscopy; XAS: X-ray absorption spectroscopy; CV: cyclic voltammetry; AOR: ammonia oxidation reaction; UV: ultraviolet.