Fig. 3: Structural characterizations of as-prepared Co₁/Nb₂O₅.

a XRD patterns. b Raman spectra. c XPS Co 2p spectra. d In situ CO-DRIFTS of Co₁/Nb₂O₅. e O K-edge spectra. f XANES spectra at Co K-edge. g Fourier transformed k³-weighted Co K-edge of EXAFS spectra. h EXAFS fitting in R space (inset is the model of Co₁–O₄). i 3D contour WT-EXAFS plot.