Fig. 5: CO adsorption energy of Ln-Cu influenced by Cu oxidation state.
From: Ligand-tuning copper in coordination polymers for efficient electrochemical C–C coupling
a Solid UV-vis absorption spectra of Ln-Cu. b Cu K-edge XANES spectrum of Ln-Cu. c The linear relationship between HOMO energy of ligands and UV-vis absorption wavelength along with XANES energy shift for Ln-Cu. The wavelength is the peak value of each absorption spectrum. XANES energy shift indicates the absorption energy difference compared to that of L6-Cu. d CO decay curves which shows the desorption rate of adsorbed CO on Cu active sites in different catalysts. e In situ Raman spectra of Ln-Cu at E – iR = –0.86 V. f The relationship between *CO binding strength and ηC−C coupling based on the trend of HOMO energy. The time at normalised intensity = 0.5 is denoted as t0.5, which was calculated from Fig. 5d based on the exponential equation (see details in ‘Methods’); Raman shift of *CO was picked up from the peak value of Raman spectra (shaded in blue) shown in Fig. 5e. Source data are provided as a Source data file.
