Fig. 4: Characterizations of local atomic structures and the chemical environment by EXAFS.

a, b Fourier-transform k3-weighted EXAFS spectra of Sn K-edge and Bi L3-edge of Sn–Bi alloy, bimetallic interface materials and reference samples. c, d Representative fitting of the EXAFS spectra to the R space of Sn K-edge and Bi L3-edge of Sn–Bi bimetallic interface materials. e, f In situ Fourier-transform k3-weighted EXAFS spectra for Sn K-edge and Bi L3-edge of Sn–Bi interface and alloy samples, respectively, at different applied potentials during CO2RR. g In situ Raman spectroscopic study on the intermediate adsorption for Sn–Bi interface sample at various potentials vs. RHE.