fig6

Figure 6. (A) 3D operando SR-FTIR spectra for B-FeNi-DASC; (B) Infrared signal (range 1,500 to 3,750 cm^-1) at different potentials for B-FeNi-DASC during C-N coupling; (C) Free energy for B-FeNi-DASC of urea synthesis. Reprinted with permission from ref^[34]. Copyright 2022 Nature Publishing Group; (D) Geometric structure and free energy of C-N coupling process at Cu₄-CeO₂ (H, C, N, O, Cu, and Ce atoms are labeled as white, gray, blue, red, pink, and yellow balls in the geometric structure, respectively); (E) Operando SR-FTIR spectroscopy at different potentials for Cu₁-CeO₂ during the C-N coupling. Reprinted with permission from ref^[35]. Copyright 2023 Wiley-VCH GmbH. 3D: Three-dimensional; SR-FTIR: synchrotron radiation-Fourier transform infrared spectroscopy; B-FeNi-DASC: bonded Fe-Ni diatomic sites catalyst.