Fig. 3: Electronic and fine structural characterizations.
From: Double sulfur vacancies by lithium tuning enhance CO2 electroreduction to n-propanol
a XPS spectra of CuS (lower panel) and CuSx-DSV (higher panel). b, c Normalized Cu K-edge XANES and the first derivative μ(E)/dE of CuS, CuSx-DSV, Cu foil, standard CuS, and Cu2S samples. d Fourier-transformed k2χ(k) of CuS (lower panel) and CuSx-DSV (upper panel). The insets in d are (100) facets on CuS without (lower inset) or with (upper inset) adjacent double sulfur vacancies. The black dashed cycles represent an adjacent sulfur vacancy pair. The decreased coordination number and scattering Cu–S path length (the extracted fitting results in Supplementary Table 4) suggest the absence of sulfur atoms around copper.
