Fig. 5. (a) Schematic illustration for the preparation of Ni–N/C_Y_H₂O/SBA-15 composites with different Phen to NiAc₂ precursor ratios. (b) Ni K-edge XANES spectra of Ni–N/C_Y_H₂O/SBA-15 composites, NiAc₂, and NiPhen₃ and their enlarged spectra in the pre-edge region. (c) FT-IR spectra of Ni–N/C_Y_H₂O/SBA-15 composites and SBA-15, Phen, and NiPhen₃ and their enlarged spectra in the regions of C–N vibration and C–H, CH₂ bending.