Fig. 2: Structural characterization of NC and Cu1/NC.
From: Sequential co-reduction of nitrate and carbon dioxide enables selective urea electrosynthesis

a, d HAADF-STEM images of NC (a) and Cu1/NC (d). b, e N 1s XPS spectra of NC (b) and Cu1/NC (e). c, f Local structures of typical C=N−H species in NC (c) and N−Cu species in Cu1/NC (f). Colour code: N, blue; C, black; H, yellow; Cu, pink.